79721955 has 32 divisors (see below), whose sum is σ = 143078400. Its totient is φ = 42113376.

The previous prime is 79721951. The next prime is 79721963. The reversal of 79721955 is 55912797.

It is not a de Polignac number, because 79721955 - 2² = 79721951 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 79721955.

It is not an unprimeable number, because it can be changed into a prime (79721951) 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 31 ways as a sum of consecutive naturals, for example, 11686 + ... + 17204.

It is an arithmetic number, because the mean of its divisors is an integer number (4471200).

Almost surely, 2^79721955 is an apocalyptic number.

79721955 is a deficient number, since it is larger than the sum of its proper divisors (63356445).

79721955 is a wasteful number, since it uses less digits than its factorization.

79721955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5640 (or 5634 counting only the distinct ones).

The product of its digits is 198450, while the sum is 45.

The square root of 79721955 is about 8928.7151931283. The cubic root of 79721955 is about 430.3871670689.

The spelling of 79721955 in words is "seventy-nine million, seven hundred twenty-one thousand, nine hundred fifty-five".