124

This number is a composite.

124 is the smallest number whose sum of digits as well as the number itself are one less than the cube of a prime. [Gupta]

The sum of the 3^rd to (2*5)^th prime numbers (5 + 7 + ... + 29 = 124). [Thoms]

124 = sigma(1!*2!*4!). Note that 124 is the smallest multi-digit number with this property. [Firoozbakht]

The concatenation of 1^124, 2^124, 3^124, 4^124, 5^124, 6^124, and 7^124 in order is a 463-digit prime number. [Gaydos]

The sum 0^0+1^1+2^2+ … +123^123+124^124 is a 260-digit prime number. [Gaydos]

Smallest positive integer k such that k*p+1 cannot be a perfect power if p is prime. [Xayah]