12515891 has 4 divisors (see below), whose sum is σ = 12674400. Its totient is φ = 12357384.

The previous prime is 12515873. The next prime is 12515903. The reversal of 12515891 is 19851521.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19851521 = 53 ⋅374557.

It is a cyclic number.

It is not a de Polignac number, because 12515891 - 2⁶ = 12515827 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12515491) 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, 79136 + ... + 79293.

It is an arithmetic number, because the mean of its divisors is an integer number (3168600).

Almost surely, 2^12515891 is an apocalyptic number.

12515891 is a deficient number, since it is larger than the sum of its proper divisors (158509).

12515891 is an equidigital number, since it uses as much as digits as its factorization.

12515891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158508.

The product of its digits is 3600, while the sum is 32.

The square root of 12515891 is about 3537.7805189130. The cubic root of 12515891 is about 232.1777460192.

The spelling of 12515891 in words is "twelve million, five hundred fifteen thousand, eight hundred ninety-one".