12400521 has 16 divisors (see below), whose sum is σ = 19891200. Its totient is φ = 6712848.

The previous prime is 12400517. The next prime is 12400541. The reversal of 12400521 is 12500421.

It is not a de Polignac number, because 12400521 - 2² = 12400517 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 12400521.

It is not an unprimeable number, because it can be changed into a prime (12400511) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15141 + ... + 15938.

It is an arithmetic number, because the mean of its divisors is an integer number (1243200).

Almost surely, 2^12400521 is an apocalyptic number.

It is an amenable number.

12400521 is a deficient number, since it is larger than the sum of its proper divisors (7490679).

12400521 is a wasteful number, since it uses less digits than its factorization.

12400521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31108.

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 12400521 is about 3521.4373485837. The cubic root of 12400521 is about 231.4621470763.

Adding to 12400521 its reverse (12500421), we get a palindrome (24900942).

It can be divided in two parts, 12400 and 521, that added together give a palindrome (12921).

The spelling of 12400521 in words is "twelve million, four hundred thousand, five hundred twenty-one".