81560372939 has 4 divisors (see below), whose sum is σ = 82401201624. Its totient is φ = 80719544256.

The previous prime is 81560372921. The next prime is 81560372941. The reversal of 81560372939 is 93927306518.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93927306518 = 2 ⋅46963653259.

It is a cyclic number.

It is not a de Polignac number, because 81560372939 - 2⁸ = 81560372683 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81560372969) 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, 420414197 + ... + 420414390.

It is an arithmetic number, because the mean of its divisors is an integer number (20600300406).

Almost surely, 2^81560372939 is an apocalyptic number.

81560372939 is a deficient number, since it is larger than the sum of its proper divisors (840828685).

81560372939 is an equidigital number, since it uses as much as digits as its factorization.

81560372939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 840828684.

The product of its (nonzero) digits is 2449440, while the sum is 53.

The spelling of 81560372939 in words is "eighty-one billion, five hundred sixty million, three hundred seventy-two thousand, nine hundred thirty-nine".