81955972 has 24 divisors (see below), whose sum is σ = 169565760. Its totient is φ = 33912480.

The previous prime is 81955927. The next prime is 81956027. The reversal of 81955972 is 27955918.

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, 49654 + ... + 51277.

It is an arithmetic number, because the mean of its divisors is an integer number (7065240).

Almost surely, 2^81955972 is an apocalyptic number.

It is an amenable number.

81955972 is an abundant number, since it is smaller than the sum of its proper divisors (87609788).

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

81955972 is a wasteful number, since it uses less digits than its factorization.

81955972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100971 (or 100969 counting only the distinct ones).

The product of its digits is 226800, while the sum is 46.

The square root of 81955972 is about 9052.9537721122. The cubic root of 81955972 is about 434.3703790340.

The spelling of 81955972 in words is "eighty-one million, nine hundred fifty-five thousand, nine hundred seventy-two".