12917521 has 4 divisors (see below), whose sum is σ = 12985344. Its totient is φ = 12849700.

The previous prime is 12917507. The next prime is 12917563. The reversal of 12917521 is 12571921.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 12917521 - 2¹⁹ = 12393233 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 12917521.

It is not an unprimeable number, because it can be changed into a prime (12917581) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33625 + ... + 34006.

It is an arithmetic number, because the mean of its divisors is an integer number (3246336).

Almost surely, 2^12917521 is an apocalyptic number.

It is an amenable number.

12917521 is a deficient number, since it is larger than the sum of its proper divisors (67823).

12917521 is an equidigital number, since it uses as much as digits as its factorization.

12917521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67822.

The product of its digits is 1260, while the sum is 28.

The square root of 12917521 is about 3594.0952964550. The cubic root of 12917521 is about 234.6351422855.

The spelling of 12917521 in words is "twelve million, nine hundred seventeen thousand, five hundred twenty-one".