81638496472 has 32 divisors (see below), whose sum is σ = 170531348400. Its totient is φ = 36380018304.

The previous prime is 81638496437. The next prime is 81638496493. The reversal of 81638496472 is 27469483618.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (58).

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, 13531218 + ... + 13537249.

Almost surely, 2^81638496472 is an apocalyptic number.

It is an amenable number.

81638496472 is an abundant number, since it is smaller than the sum of its proper divisors (88892851928).

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

81638496472 is a wasteful number, since it uses less digits than its factorization.

81638496472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27068515 (or 27068511 counting only the distinct ones).

The product of its digits is 13934592, while the sum is 58.

The spelling of 81638496472 in words is "eighty-one billion, six hundred thirty-eight million, four hundred ninety-six thousand, four hundred seventy-two".