79699991 has 16 divisors (see below), whose sum is σ = 95660544. Its totient is φ = 64921824.

The previous prime is 79699981. The next prime is 79699999. The reversal of 79699991 is 19999697.

It is a de Polignac number, because none of the positive numbers 2^k-79699991 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 79699991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79699999) 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, 24725 + ... + 27761.

It is an arithmetic number, because the mean of its divisors is an integer number (5978784).

Almost surely, 2^79699991 is an apocalyptic number.

79699991 is a deficient number, since it is larger than the sum of its proper divisors (15960553).

79699991 is a wasteful number, since it uses less digits than its factorization.

79699991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3230.

The product of its digits is 2480058, while the sum is 59.

The square root of 79699991 is about 8927.4851442049. The cubic root of 79699991 is about 430.3476384681.

The spelling of 79699991 in words is "seventy-nine million, six hundred ninety-nine thousand, nine hundred ninety-one".