79423991 has 4 divisors (see below), whose sum is σ = 82877232. Its totient is φ = 75970752.

The previous prime is 79423979. The next prime is 79423997. The reversal of 79423991 is 19932497.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-79423991 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 (79423997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1726586 + ... + 1726631.

It is an arithmetic number, because the mean of its divisors is an integer number (20719308).

Almost surely, 2^79423991 is an apocalyptic number.

79423991 is a deficient number, since it is larger than the sum of its proper divisors (3453241).

79423991 is a wasteful number, since it uses less digits than its factorization.

79423991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3453240.

The product of its digits is 122472, while the sum is 44.

The square root of 79423991 is about 8912.0138577092. The cubic root of 79423991 is about 429.8503012346.

The spelling of 79423991 in words is "seventy-nine million, four hundred twenty-three thousand, nine hundred ninety-one".