81664092 has 24 divisors (see below), whose sum is σ = 211722000. Its totient is φ = 27221328.

The previous prime is 81664067. The next prime is 81664111. The reversal of 81664092 is 29046618.

81664092 is a `hidden beast` number, since 8 + 1 + 6 + 640 + 9 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 377967 + ... + 378182.

It is an arithmetic number, because the mean of its divisors is an integer number (8821750).

Almost surely, 2^81664092 is an apocalyptic number.

It is an amenable number.

81664092 is an abundant number, since it is smaller than the sum of its proper divisors (130057908).

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

81664092 is a wasteful number, since it uses less digits than its factorization.

81664092 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 756162 (or 756154 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 81664092 is about 9036.8186880118. The cubic root of 81664092 is about 433.8541065680.

It can be divided in two parts, 8 and 1664092, that added together give a square (1664100 = 1290²).

The spelling of 81664092 in words is "eighty-one million, six hundred sixty-four thousand, ninety-two".