81125356937 has 4 divisors (see below), whose sum is σ = 82102770960. Its totient is φ = 80147942916.

The previous prime is 81125356919. The next prime is 81125356943. The reversal of 81125356937 is 73965352118.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81125356937 - 2⁸ = 81125356681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81125356997) 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, 488706887 + ... + 488707052.

It is an arithmetic number, because the mean of its divisors is an integer number (20525692740).

Almost surely, 2^81125356937 is an apocalyptic number.

It is an amenable number.

81125356937 is a deficient number, since it is larger than the sum of its proper divisors (977414023).

81125356937 is an equidigital number, since it uses as much as digits as its factorization.

81125356937 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 977414022.

The product of its digits is 1360800, while the sum is 50.

The spelling of 81125356937 in words is "eighty-one billion, one hundred twenty-five million, three hundred fifty-six thousand, nine hundred thirty-seven".