13215857 has 4 divisors (see below), whose sum is σ = 13264896. Its totient is φ = 13166820.

The previous prime is 13215821. The next prime is 13215859. The reversal of 13215857 is 75851231.

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, and also an emirpimes, since its reverse is a distinct semiprime: 75851231 = 4091 ⋅18541.

It is a cyclic number.

It is not a de Polignac number, because 13215857 - 2²² = 9021553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13215859) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24113 + ... + 24654.

It is an arithmetic number, because the mean of its divisors is an integer number (3316224).

Almost surely, 2^13215857 is an apocalyptic number.

It is an amenable number.

13215857 is a deficient number, since it is larger than the sum of its proper divisors (49039).

13215857 is an equidigital number, since it uses as much as digits as its factorization.

13215857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49038.

The product of its digits is 8400, while the sum is 32.

The square root of 13215857 is about 3635.3620177363. The cubic root of 13215857 is about 236.4277469404.

The spelling of 13215857 in words is "thirteen million, two hundred fifteen thousand, eight hundred fifty-seven".