81039988 has 12 divisors (see below), whose sum is σ = 143197600. Its totient is φ = 40126392.

The previous prime is 81039979. The next prime is 81040049. The reversal of 81039988 is 88993018.

It is a hoax number, since the sum of its digits (46) coincides with the sum of the digits of its distinct prime factors.

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, 97938 + ... + 98761.

Almost surely, 2^81039988 is an apocalyptic number.

It is an amenable number.

81039988 is a deficient number, since it is larger than the sum of its proper divisors (62157612).

81039988 is a wasteful number, since it uses less digits than its factorization.

81039988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196806 (or 196804 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 46.

The square root of 81039988 is about 9002.2212814394. The cubic root of 81039988 is about 432.7460602130.

The spelling of 81039988 in words is "eighty-one million, thirty-nine thousand, nine hundred eighty-eight".