79691978 has 8 divisors (see below), whose sum is σ = 122081472. Its totient is φ = 38998156.

The previous prime is 79691977. The next prime is 79691993. The reversal of 79691978 is 87919697.

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

It is a super-2 number, since 2×79691978² = 12701622715104968, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (79691977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 423800 + ... + 423987.

It is an arithmetic number, because the mean of its divisors is an integer number (15260184).

Almost surely, 2^79691978 is an apocalyptic number.

79691978 is a deficient number, since it is larger than the sum of its proper divisors (42389494).

79691978 is a wasteful number, since it uses less digits than its factorization.

79691978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 847836.

The product of its digits is 1714608, while the sum is 56.

The square root of 79691978 is about 8927.0363503237. The cubic root of 79691978 is about 430.3332156676. Note that the first 3 decimals are identical.

The spelling of 79691978 in words is "seventy-nine million, six hundred ninety-one thousand, nine hundred seventy-eight".