56139991 has 2 divisors, whose sum is σ = 56139992. Its totient is φ = 56139990.

The previous prime is 56139959. The next prime is 56140009. The reversal of 56139991 is 19993165.

56139991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 56139991 - 2⁵ = 56139959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (56139931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28069995 + 28069996.

It is an arithmetic number, because the mean of its divisors is an integer number (28069996).

Almost surely, 2^56139991 is an apocalyptic number.

56139991 is a deficient number, since it is larger than the sum of its proper divisors (1).

56139991 is an equidigital number, since it uses as much as digits as its factorization.

56139991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 65610, while the sum is 43.

The square root of 56139991 is about 7492.6624773841. The cubic root of 56139991 is about 382.9047726402.

It can be divided in two parts, 561 and 39991, that multiplied together give a triangular number (22434951 = T₆₆₉₈).

The spelling of 56139991 in words is "fifty-six million, one hundred thirty-nine thousand, nine hundred ninety-one".