12815917 has 4 divisors (see below), whose sum is σ = 13026076. Its totient is φ = 12605760.

The previous prime is 12815867. The next prime is 12815923. The reversal of 12815917 is 71951821.

It is a happy number.

12815917 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71951821 = 139 ⋅517639.

It can be written as a sum of positive squares in 2 ways, for example, as 3261636 + 9554281 = 1806^2 + 3091^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12815917 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12815017) 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, 104988 + ... + 105109.

It is an arithmetic number, because the mean of its divisors is an integer number (3256519).

Almost surely, 2^12815917 is an apocalyptic number.

It is an amenable number.

12815917 is a deficient number, since it is larger than the sum of its proper divisors (210159).

12815917 is an equidigital number, since it uses as much as digits as its factorization.

12815917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210158.

The product of its digits is 5040, while the sum is 34.

The square root of 12815917 is about 3579.9325412639. The cubic root of 12815917 is about 234.0183405402.

The spelling of 12815917 in words is "twelve million, eight hundred fifteen thousand, nine hundred seventeen".