81161968 has 20 divisors (see below), whose sum is σ = 162324928. Its totient is φ = 39271680.

The previous prime is 81161957. The next prime is 81161987. The reversal of 81161968 is 86916118.

81161968 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 81161968.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81321 + ... + 82312.

Almost surely, 2^81161968 is an apocalyptic number.

It is an amenable number.

81161968 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

81161968 is a wasteful number, since it uses less digits than its factorization.

81161968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163672 (or 163666 counting only the distinct ones).

The product of its digits is 20736, while the sum is 40.

The square root of 81161968 is about 9008.9937284915. The cubic root of 81161968 is about 432.9630720178.

The spelling of 81161968 in words is "eighty-one million, one hundred sixty-one thousand, nine hundred sixty-eight".