79921539 has 16 divisors (see below), whose sum is σ = 125367840. Its totient is φ = 50146560.

The previous prime is 79921507. The next prime is 79921559. The reversal of 79921539 is 93512997.

It is a happy number.

79921539 is a `hidden beast` number, since 7 + 99 + 21 + 539 = 666.

It is not a de Polignac number, because 79921539 - 2⁵ = 79921507 is a prime.

It is a super-2 number, since 2×79921539² = 12774904792257042, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 79921494 and 79921503.

It is not an unprimeable number, because it can be changed into a prime (79921559) 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, 86602 + ... + 87519.

It is an arithmetic number, because the mean of its divisors is an integer number (7835490).

Almost surely, 2^79921539 is an apocalyptic number.

79921539 is a deficient number, since it is larger than the sum of its proper divisors (45446301).

79921539 is a wasteful number, since it uses less digits than its factorization.

79921539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174147 (or 174141 counting only the distinct ones).

The product of its digits is 153090, while the sum is 45.

The square root of 79921539 is about 8939.8847308005. The cubic root of 79921539 is about 430.7460260124.

The spelling of 79921539 in words is "seventy-nine million, nine hundred twenty-one thousand, five hundred thirty-nine".