79919999 has 8 divisors (see below), whose sum is σ = 80923920. Its totient is φ = 78921216.

The previous prime is 79919989. The next prime is 79920019. The reversal of 79919999 is 99991997.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-79919999 is a prime.

It is a Duffinian number.

79919999 is a modest number, since divided by 9999 gives 7991 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79919989) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36767 + ... + 38879.

It is an arithmetic number, because the mean of its divisors is an integer number (10115490).

Almost surely, 2^79919999 is an apocalyptic number.

79919999 is a deficient number, since it is larger than the sum of its proper divisors (1003921).

79919999 is a wasteful number, since it uses less digits than its factorization.

79919999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2569.

The product of its digits is 3720087, while the sum is 62.

The square root of 79919999 is about 8939.7985995211. The cubic root of 79919999 is about 430.7432593275.

The spelling of 79919999 in words is "seventy-nine million, nine hundred nineteen thousand, nine hundred ninety-nine".