81811632 has 40 divisors (see below), whose sum is σ = 241540096. Its totient is φ = 23374656.

The previous prime is 81811589. The next prime is 81811651. The reversal of 81811632 is 23611818.

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 81811632.

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, 121408 + ... + 122079.

Almost surely, 2^81811632 is an apocalyptic number.

It is an amenable number.

81811632 is an abundant number, since it is smaller than the sum of its proper divisors (159728464).

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

81811632 is a wasteful number, since it uses less digits than its factorization.

81811632 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243505 (or 243499 counting only the distinct ones).

The product of its digits is 2304, while the sum is 30.

The square root of 81811632 is about 9044.9782752641. The cubic root of 81811632 is about 434.1152263297.

The spelling of 81811632 in words is "eighty-one million, eight hundred eleven thousand, six hundred thirty-two".