79521509 has 16 divisors (see below), whose sum is σ = 86123520. Its totient is φ = 73261440.

The previous prime is 79521503. The next prime is 79521523. The reversal of 79521509 is 90512597.

It is a cyclic number.

It is not a de Polignac number, because 79521509 - 2⁴ = 79521493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79521503) 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, 55172 + ... + 56594.

It is an arithmetic number, because the mean of its divisors is an integer number (5382720).

Almost surely, 2^79521509 is an apocalyptic number.

It is an amenable number.

79521509 is a deficient number, since it is larger than the sum of its proper divisors (6602011).

79521509 is a wasteful number, since it uses less digits than its factorization.

79521509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1540.

The product of its (nonzero) digits is 28350, while the sum is 38.

The square root of 79521509 is about 8917.4833333178. The cubic root of 79521509 is about 430.0261548901.

The spelling of 79521509 in words is "seventy-nine million, five hundred twenty-one thousand, five hundred nine".