81999792 has 60 divisors (see below), whose sum is σ = 262272400. Its totient is φ = 23428224.

The previous prime is 81999781. The next prime is 81999803. The reversal of 81999792 is 29799918.

It is an interprime number because it is at equal distance from previous prime (81999781) and next prime (81999803).

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

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 39667 + ... + 41682.

Almost surely, 2^81999792 is an apocalyptic number.

It is an amenable number.

81999792 is an abundant number, since it is smaller than the sum of its proper divisors (180272608).

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

81999792 is a wasteful number, since it uses less digits than its factorization.

81999792 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81370 (or 81361 counting only the distinct ones).

The product of its digits is 734832, while the sum is 54.

The square root of 81999792 is about 9055.3736532514. The cubic root of 81999792 is about 434.4477812383.

The spelling of 81999792 in words is "eighty-one million, nine hundred ninety-nine thousand, seven hundred ninety-two".