81812908 has 24 divisors (see below), whose sum is σ = 151934832. Its totient is φ = 38413824.

The previous prime is 81812897. The next prime is 81812921. The reversal of 81812908 is 80921818.

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37216 + ... + 39352.

It is an arithmetic number, because the mean of its divisors is an integer number (6330618).

Almost surely, 2^81812908 is an apocalyptic number.

It is an amenable number.

81812908 is a deficient number, since it is larger than the sum of its proper divisors (70121924).

81812908 is a wasteful number, since it uses less digits than its factorization.

81812908 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2721 (or 2719 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 37.

The square root of 81812908 is about 9045.0488113664. The cubic root of 81812908 is about 434.1174832547.

The spelling of 81812908 in words is "eighty-one million, eight hundred twelve thousand, nine hundred eight".