2,400

[Calendar]  This year is a leap year, following the adoption of the current Gregorian calendar, created by Pope Gregory XIII in 1582 to reform the old Julian calendar.

 

[EECS]  2.4K(W) is one of standard numerical values for resistors (of tolerance class 5%).

 

[Geology]  The length (miles) of the historic Route 66, through 8 states: Illinois (beginning in Grant Park on the shore of Lake Michigan, Chicago), Missouri (St. Louis), Kansas, Oklahoma (Oklahoma City), Texas (Amarillo), New Mexico (Albuquerque), Arizona (Flagstaff) and California (ending at the Santa Monica Pier, Los Angeles).

 

[Tech.]  One of standardized baud rate (bits per second) in electronic data transmissions.

 

[Tech.]  Microwave ovens operate at frequency ranges of either 890-915 MHz or 2400-2500 MHz.

 

[Military]  Military time of a day set from midnight (0000) to midnight of the next day (2400), using 4-digit format hhmm, the first 2 digits hh for hours (from 00 to 24) and the last 2 digits mm minutes (from 00 to 59).

 

2,401

[Math.]  2,401 = (2+4+0+1)4 = 74.

 

2,407

[Math.]  2,047 = 23×89 and 2,407 = 29×83.

 

2,415

[Math.]  A triangular number (sum of all integers from 1 to 69): 2415 = 1+2+…+68+69.

 

2,418

[Math.]    13×93 = 1,209 = 31×39

               26×93 = 2,418 = 62×39

               13×62 = 806 = 31×26.

 

2,422 & 2,431

[Sport]  One of soccer’s possible lineup tactics formations: 2-4-4 (2 defenders, 4 midfielders and 4 forwards). A slightly modified forwards line makes: 2-4-3-1 (1 striker) or 2-4-2-2 (2 strikers).

 

2,427

[Math.]  2427 = 21+42+23+74.

 

2,450

[Math.]  (Sequence of numbers 49…950…0 and 50…050…0).

24,502,500 = (2450+2500)2 = 49502 and

25,502,500 = (2550+2500)2 = 50502 and 4950+5050 = 10000.

 

2,457

[Math.]  Two consecutive sums of consecutive numbers:

169+170+…+182 = 183+184+…+195 = 2457.

 

2,465

[Math.]  The 4th Carmichael number: 2465 = 5×17×29.

 

2,467

[Math.]  24672 = 6,086,089.

 

2,468

[Zip]  U.S. Postal Zip Code: Waban, Massachusetts 02468. (All even digits).

 

2,469

[Math.]  Two multiples of 2469, 2469×4 = 9,876 and 2469×5 = 12,345, use each of 9 digits 1-9 once.

 

2,470

[Math.]   A pyramidal number (sum of all squares of integers from 1 to 19): 2470 = 12+22+…+182+192.

 

2,485

[Math.]  A triangular number (sum of all integers from 1 to 70): 2485 = 1+2+…+69+70.

 

2,499

[Math.]  The number of 0’s that the factorial (10,000!) ends in.

2499 = [[10,000/5]]+[[10,000/52]]+…+[[10,000/55]], 

 where [[x]] is the floor function of x, i.e. which is the largest integer less than x (or the integral part of x).