81799904 has 24 divisors (see below), whose sum is σ = 161767368. Its totient is φ = 40716160.

The previous prime is 81799897. The next prime is 81799973. The reversal of 81799904 is 40999718.

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, 1634 + ... + 12894.

It is an arithmetic number, because the mean of its divisors is an integer number (6740307).

Almost surely, 2^81799904 is an apocalyptic number.

It is an amenable number.

81799904 is a deficient number, since it is larger than the sum of its proper divisors (79967464).

81799904 is a wasteful number, since it uses less digits than its factorization.

81799904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11498 (or 11490 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 47.

The square root of 81799904 is about 9044.3299364851. The cubic root of 81799904 is about 434.0944813307.

The spelling of 81799904 in words is "eighty-one million, seven hundred ninety-nine thousand, nine hundred four".