81912432 has 40 divisors (see below), whose sum is σ = 241837696. Its totient is φ = 23403456.

The previous prime is 81912427. The next prime is 81912449. The reversal of 81912432 is 23421918.

It is a self number, because there is not a number n which added to its sum of digits gives 81912432.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 121558 + ... + 122229.

Almost surely, 2^81912432 is an apocalyptic number.

It is an amenable number.

81912432 is an abundant number, since it is smaller than the sum of its proper divisors (159925264).

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

81912432 is a wasteful number, since it uses less digits than its factorization.

81912432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243805 (or 243799 counting only the distinct ones).

The product of its digits is 3456, while the sum is 30.

The square root of 81912432 is about 9050.5487126472. The cubic root of 81912432 is about 434.2934440815.

The spelling of 81912432 in words is "eighty-one million, nine hundred twelve thousand, four hundred thirty-two".