56979991 has 2 divisors, whose sum is σ = 56979992. Its totient is φ = 56979990.

The previous prime is 56979977. The next prime is 56980051. The reversal of 56979991 is 19997965.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 56979991 - 2⁵ = 56979959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (56979691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28489995 + 28489996.

It is an arithmetic number, because the mean of its divisors is an integer number (28489996).

Almost surely, 2^56979991 is an apocalyptic number.

56979991 is a deficient number, since it is larger than the sum of its proper divisors (1).

56979991 is an equidigital number, since it uses as much as digits as its factorization.

56979991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1377810, while the sum is 55.

The square root of 56979991 is about 7548.5091905621. The cubic root of 56979991 is about 384.8050758930.

It can be divided in two parts, 56979 and 991, that added together give a triangular number (57970 = T₃₄₀).

The spelling of 56979991 in words is "fifty-six million, nine hundred seventy-nine thousand, nine hundred ninety-one".