79721369 has 16 divisors (see below), whose sum is σ = 98638848. Its totient is φ = 62741952.

The previous prime is 79721339. The next prime is 79721371. The reversal of 79721369 is 96312797.

It is a happy number.

It is not a de Polignac number, because 79721369 - 2¹² = 79717273 is a prime.

It is a super-2 number, since 2×79721369² = 12710993350468322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (79721339) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15704 + ... + 20150.

It is an arithmetic number, because the mean of its divisors is an integer number (6164928).

Almost surely, 2^79721369 is an apocalyptic number.

It is an amenable number.

79721369 is a deficient number, since it is larger than the sum of its proper divisors (18917479).

79721369 is a wasteful number, since it uses less digits than its factorization.

79721369 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4664.

The product of its digits is 142884, while the sum is 44.

The square root of 79721369 is about 8928.6823775964. The cubic root of 79721369 is about 430.3861125392.

The spelling of 79721369 in words is "seventy-nine million, seven hundred twenty-one thousand, three hundred sixty-nine".