79128657 has 20 divisors (see below), whose sum is σ = 118444480. Its totient is φ = 52645464.

The previous prime is 79128653. The next prime is 79128661. The reversal of 79128657 is 75682197.

It is an interprime number because it is at equal distance from previous prime (79128653) and next prime (79128661).

It is not a de Polignac number, because 79128657 - 2² = 79128653 is a prime.

It is a super-2 number, since 2×79128657² = 12522688717247298, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (79128653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 73908 + ... + 74970.

It is an arithmetic number, because the mean of its divisors is an integer number (5922224).

It is a vampire number, since it can be written as 8271 ⋅ 9567 (with its own digits).

Almost surely, 2^79128657 is an apocalyptic number.

It is an amenable number.

79128657 is a deficient number, since it is larger than the sum of its proper divisors (39315823).

79128657 is a wasteful number, since it uses less digits than its factorization.

79128657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1994 (or 1985 counting only the distinct ones).

The product of its digits is 211680, while the sum is 45.

The square root of 79128657 is about 8895.4289947141. The cubic root of 79128657 is about 429.3168474476.

The spelling of 79128657 in words is "seventy-nine million, one hundred twenty-eight thousand, six hundred fifty-seven".