81923988 has 36 divisors (see below), whose sum is σ = 193682048. Its totient is φ = 26951760.

The previous prime is 81923981. The next prime is 81924001. The reversal of 81923988 is 88932918.

It is a happy number.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81923981) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 82173 + ... + 83163.

Almost surely, 2^81923988 is an apocalyptic number.

It is an amenable number.

81923988 is an abundant number, since it is smaller than the sum of its proper divisors (111758060).

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

81923988 is a wasteful number, since it uses less digits than its factorization.

81923988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1164 (or 1079 counting only the distinct ones).

The product of its digits is 248832, while the sum is 48.

The square root of 81923988 is about 9051.1871044631. The cubic root of 81923988 is about 434.3138661303.

The spelling of 81923988 in words is "eighty-one million, nine hundred twenty-three thousand, nine hundred eighty-eight".