79939999 has 4 divisors (see below), whose sum is σ = 80550360. Its totient is φ = 79329640.

The previous prime is 79939991. The next prime is 79940009. The reversal of 79939999 is 99993997.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 79939999 - 2³ = 79939991 is a prime.

It is a Duffinian number.

79939999 is a modest number, since divided by 9999 gives 7993 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 79939999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79939991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 304984 + ... + 305245.

It is an arithmetic number, because the mean of its divisors is an integer number (20137590).

Almost surely, 2^79939999 is an apocalyptic number.

79939999 is a deficient number, since it is larger than the sum of its proper divisors (610361).

79939999 is a wasteful number, since it uses less digits than its factorization.

79939999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 610360.

The product of its digits is 11160261, while the sum is 64.

The square root of 79939999 is about 8940.9171229802. The cubic root of 79939999 is about 430.7791875340.

The spelling of 79939999 in words is "seventy-nine million, nine hundred thirty-nine thousand, nine hundred ninety-nine".