81920912 has 40 divisors (see below), whose sum is σ = 162043200. Its totient is φ = 40113792.

The previous prime is 81920899. The next prime is 81920929. The reversal of 81920912 is 21902918.

It is a happy number.

It is a super-2 number, since 2×81920912² = 13422071645823488, which contains 22 as substring.

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, 186389 + ... + 186827.

It is an arithmetic number, because the mean of its divisors is an integer number (4051080).

Almost surely, 2^81920912 is an apocalyptic number.

It is an amenable number.

81920912 is a deficient number, since it is larger than the sum of its proper divisors (80122288).

81920912 is a wasteful number, since it uses less digits than its factorization.

81920912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 663 (or 657 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 81920912 is about 9051.0171804057. The cubic root of 81920912 is about 434.3084303347.

The spelling of 81920912 in words is "eighty-one million, nine hundred twenty thousand, nine hundred twelve".