81790868 has 24 divisors (see below), whose sum is σ = 148029000. Its totient is φ = 39512448.

The previous prime is 81790867. The next prime is 81790873. The reversal of 81790868 is 86809718.

It can be written as a sum of positive squares in 4 ways, for example, as 6240004 + 75550864 = 2498^2 + 8692^2 .

It is a Smith number, since the sum of its digits (47) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81790861) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20198 + ... + 23906.

It is an arithmetic number, because the mean of its divisors is an integer number (6167875).

Almost surely, 2^81790868 is an apocalyptic number.

It is an amenable number.

81790868 is a deficient number, since it is larger than the sum of its proper divisors (66238132).

81790868 is a wasteful number, since it uses less digits than its factorization.

81790868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3899 (or 3897 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 47.

The square root of 81790868 is about 9043.8303831949. The cubic root of 81790868 is about 434.0784967065.

The spelling of 81790868 in words is "eighty-one million, seven hundred ninety thousand, eight hundred sixty-eight".