81206916 has 36 divisors (see below), whose sum is σ = 220420368. Its totient is φ = 23201808.

The previous prime is 81206903. The next prime is 81206947. The reversal of 81206916 is 61960218.

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 11 ways as a sum of consecutive naturals, for example, 68466 + ... + 69641.

It is an arithmetic number, because the mean of its divisors is an integer number (6122788).

Almost surely, 2^81206916 is an apocalyptic number.

It is an amenable number.

81206916 is an abundant number, since it is smaller than the sum of its proper divisors (139213452).

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

81206916 is a wasteful number, since it uses less digits than its factorization.

81206916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138128 (or 138119 counting only the distinct ones).

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

The square root of 81206916 is about 9011.4880014346. The cubic root of 81206916 is about 433.0429831438.

The spelling of 81206916 in words is "eighty-one million, two hundred six thousand, nine hundred sixteen".