81956012 has 6 divisors (see below), whose sum is σ = 143423028. Its totient is φ = 40978004.

The previous prime is 81955927. The next prime is 81956027. The reversal of 81956012 is 21065918.

It is a self number, because there is not a number n which added to its sum of digits gives 81956012.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10244498 + ... + 10244505.

It is an arithmetic number, because the mean of its divisors is an integer number (23903838).

Almost surely, 2^81956012 is an apocalyptic number.

It is an amenable number.

81956012 is a deficient number, since it is larger than the sum of its proper divisors (61467016).

81956012 is a wasteful number, since it uses less digits than its factorization.

81956012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20489007 (or 20489005 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 32.

The square root of 81956012 is about 9052.9559813356. The cubic root of 81956012 is about 434.3704497013.

The spelling of 81956012 in words is "eighty-one million, nine hundred fifty-six thousand, twelve".