12515581 has 4 divisors (see below), whose sum is σ = 13478332. Its totient is φ = 11552832.

The previous prime is 12515567. The next prime is 12515597. The reversal of 12515581 is 18551521.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18551521 = 277 ⋅66973.

It can be written as a sum of positive squares in 2 ways, for example, as 3115225 + 9400356 = 1765^2 + 3066^2 .

It is a cyclic number.

It is not a de Polignac number, because 12515581 - 2⁵ = 12515549 is a prime.

It is a super-2 number, since 2×12515581² = 313279535535122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12515521) 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, 481356 + ... + 481381.

It is an arithmetic number, because the mean of its divisors is an integer number (3369583).

Almost surely, 2^12515581 is an apocalyptic number.

It is an amenable number.

12515581 is a deficient number, since it is larger than the sum of its proper divisors (962751).

12515581 is an equidigital number, since it uses as much as digits as its factorization.

12515581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 962750.

The product of its digits is 2000, while the sum is 28.

The square root of 12515581 is about 3537.7367058615. The cubic root of 12515581 is about 232.1758291042.

The spelling of 12515581 in words is "twelve million, five hundred fifteen thousand, five hundred eighty-one".