81755904 has 36 divisors (see below), whose sum is σ = 217591976. Its totient is φ = 27251712.

The previous prime is 81755893. The next prime is 81755909. The reversal of 81755904 is 40955718.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81755909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52459 + ... + 53994.

Almost surely, 2^81755904 is an apocalyptic number.

It is an amenable number.

81755904 is an abundant number, since it is smaller than the sum of its proper divisors (135836072).

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

81755904 is a wasteful number, since it uses less digits than its factorization.

81755904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106472 (or 106458 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 39.

The square root of 81755904 is about 9041.8971460640. The cubic root of 81755904 is about 434.0166345284.

The spelling of 81755904 in words is "eighty-one million, seven hundred fifty-five thousand, nine hundred four".