81860816 has 40 divisors (see below), whose sum is σ = 168501120. Its totient is φ = 38416896.

The previous prime is 81860791. The next prime is 81860843. The reversal of 81860816 is 61806818.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is a self number, because there is not a number n which added to its sum of digits gives 81860816.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33161 + ... + 35543.

It is an arithmetic number, because the mean of its divisors is an integer number (4212528).

Almost surely, 2^81860816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81860816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84250560).

81860816 is an abundant number, since it is smaller than the sum of its proper divisors (86640304).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81860816 is a wasteful number, since it uses less digits than its factorization.

81860816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2523 (or 2517 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 38.

The square root of 81860816 is about 9047.6967234761. The cubic root of 81860816 is about 434.2022035539.

The spelling of 81860816 in words is "eighty-one million, eight hundred sixty thousand, eight hundred sixteen".