79215681 has 4 divisors (see below), whose sum is σ = 105620912. Its totient is φ = 52810452.

The previous prime is 79215679. The next prime is 79215691. The reversal of 79215681 is 18651297.

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.

It is not a de Polignac number, because 79215681 - 2¹ = 79215679 is a prime.

It is a super-2 number, since 2×79215681² = 12550248232587522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (79215601) 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, 13202611 + ... + 13202616.

It is an arithmetic number, because the mean of its divisors is an integer number (26405228).

Almost surely, 2^79215681 is an apocalyptic number.

It is an amenable number.

79215681 is a deficient number, since it is larger than the sum of its proper divisors (26405231).

79215681 is a wasteful number, since it uses less digits than its factorization.

79215681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26405230.

The product of its digits is 30240, while the sum is 39.

The square root of 79215681 is about 8900.3191515810. The cubic root of 79215681 is about 429.4741742740.

The spelling of 79215681 in words is "seventy-nine million, two hundred fifteen thousand, six hundred eighty-one".