79558407721 has 15 divisors (see below), whose sum is σ = 86239714371. Its totient is φ = 73394528688.

The previous prime is 79558407667. The next prime is 79558407737. The reversal of 79558407721 is 12770485597.

The square root of 79558407721 is 282061.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 7 ways, for example, as 79445623321 + 112784400 = 281861^2 + 10620^2 .

It is not a de Polignac number, because 79558407721 - 2²⁹ = 79021536809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (79558407791) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 47667475 + ... + 47669143.

Almost surely, 2^79558407721 is an apocalyptic number.

79558407721 is the 282061-st square number.

79558407721 is the 141031-st centered octagonal number.

It is an amenable number.

79558407721 is a deficient number, since it is larger than the sum of its proper divisors (6681306650).

79558407721 is an frugal number, since it uses more digits than its factorization.

79558407721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3390 (or 1682 counting only the distinct ones).

The product of its (nonzero) digits is 4939200, while the sum is 55.

The spelling of 79558407721 in words is "seventy-nine billion, five hundred fifty-eight million, four hundred seven thousand, seven hundred twenty-one".