81922920 has 64 divisors (see below), whose sum is σ = 251778240. Its totient is φ = 21312000.

The previous prime is 81922873. The next prime is 81922957. The reversal of 81922920 is 2922918.

It is a happy number.

It is a super-2 number, since 2×81922920² = 13422729642652800, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3406 + ... + 13245.

It is an arithmetic number, because the mean of its divisors is an integer number (3934035).

Almost surely, 2^81922920 is an apocalyptic number.

It is an amenable number.

81922920 is an abundant number, since it is smaller than the sum of its proper divisors (169855320).

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

81922920 is a wasteful number, since it uses less digits than its factorization.

81922920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16706 (or 16702 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 81922920 is about 9051.1281064848. The cubic root of 81922920 is about 434.3119788149.

The spelling of 81922920 in words is "eighty-one million, nine hundred twenty-two thousand, nine hundred twenty".