81831968 has 48 divisors (see below), whose sum is σ = 168399000. Its totient is φ = 39094272.

The previous prime is 81831929. The next prime is 81832019. The reversal of 81831968 is 86913818.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 81504784 + 327184 = 9028^2 + 572^2 .

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, 100748 + ... + 101556.

Almost surely, 2^81831968 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81831968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84199500).

81831968 is an abundant number, since it is smaller than the sum of its proper divisors (86567032).

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

81831968 is a wasteful number, since it uses less digits than its factorization.

81831968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 957 (or 949 counting only the distinct ones).

The product of its digits is 82944, while the sum is 44.

The square root of 81831968 is about 9046.1023651073. The cubic root of 81831968 is about 434.1511928366.

The spelling of 81831968 in words is "eighty-one million, eight hundred thirty-one thousand, nine hundred sixty-eight".