81915828 has 12 divisors (see below), whose sum is σ = 191136960. Its totient is φ = 27305272.

The previous prime is 81915787. The next prime is 81915833. The reversal of 81915828 is 82851918.

It is a tau number, because it is divible by the number of its divisors (12).

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 81915828.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3413148 + ... + 3413171.

It is an arithmetic number, because the mean of its divisors is an integer number (15928080).

Almost surely, 2^81915828 is an apocalyptic number.

It is an amenable number.

81915828 is an abundant number, since it is smaller than the sum of its proper divisors (109221132).

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

81915828 is a wasteful number, since it uses less digits than its factorization.

81915828 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6826326 (or 6826324 counting only the distinct ones).

The product of its digits is 46080, while the sum is 42.

The square root of 81915828 is about 9050.7363236369. The cubic root of 81915828 is about 434.2994457759.

The spelling of 81915828 in words is "eighty-one million, nine hundred fifteen thousand, eight hundred twenty-eight".