81365851 has 16 divisors (see below), whose sum is σ = 96825600. Its totient is φ = 66896928.

The previous prime is 81365833. The next prime is 81365857. The reversal of 81365851 is 15856318.

It is not a de Polignac number, because 81365851 - 2⁵ = 81365819 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81365851.

It is not an unprimeable number, because it can be changed into a prime (81365857) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31860 + ... + 34318.

It is an arithmetic number, because the mean of its divisors is an integer number (6051600).

Almost surely, 2^81365851 is an apocalyptic number.

81365851 is a deficient number, since it is larger than the sum of its proper divisors (15459749).

81365851 is a wasteful number, since it uses less digits than its factorization.

81365851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2658.

The product of its digits is 28800, while the sum is 37.

The square root of 81365851 is about 9020.3021568016. The cubic root of 81365851 is about 433.3253106338.

The spelling of 81365851 in words is "eighty-one million, three hundred sixty-five thousand, eight hundred fifty-one".