79711921 has 2 divisors, whose sum is σ = 79711922. Its totient is φ = 79711920.

The previous prime is 79711909. The next prime is 79711967. The reversal of 79711921 is 12911797.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 56325025 + 23386896 = 7505^2 + 4836^2 .

It is a cyclic number.

It is not a de Polignac number, because 79711921 - 2⁹ = 79711409 is a prime.

It is not a weakly prime, because it can be changed into another prime (79711901) 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 as a sum of consecutive naturals, namely, 39855960 + 39855961.

It is an arithmetic number, because the mean of its divisors is an integer number (39855961).

Almost surely, 2^79711921 is an apocalyptic number.

It is an amenable number.

79711921 is a deficient number, since it is larger than the sum of its proper divisors (1).

79711921 is an equidigital number, since it uses as much as digits as its factorization.

79711921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7938, while the sum is 37.

The square root of 79711921 is about 8928.1532804942. The cubic root of 79711921 is about 430.3691097845.

The spelling of 79711921 in words is "seventy-nine million, seven hundred eleven thousand, nine hundred twenty-one".