79812021 has 4 divisors (see below), whose sum is σ = 106416032. Its totient is φ = 53208012.

The previous prime is 79812017. The next prime is 79812043. The reversal of 79812021 is 12021897.

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 79812021 - 2² = 79812017 is a prime.

It is a super-2 number, since 2×79812021² = 12739917392208882, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 79812021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79813021) 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, 13302001 + ... + 13302006.

It is an arithmetic number, because the mean of its divisors is an integer number (26604008).

Almost surely, 2^79812021 is an apocalyptic number.

It is an amenable number.

79812021 is a deficient number, since it is larger than the sum of its proper divisors (26604011).

79812021 is a wasteful number, since it uses less digits than its factorization.

79812021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26604010.

The product of its (nonzero) digits is 2016, while the sum is 30.

The square root of 79812021 is about 8933.7573842141. The cubic root of 79812021 is about 430.5491829240.

The spelling of 79812021 in words is "seventy-nine million, eight hundred twelve thousand, twenty-one".