81937968 has 40 divisors (see below), whose sum is σ = 241913088. Its totient is φ = 23410752.

The previous prime is 81937951. The next prime is 81937979. The reversal of 81937968 is 86973918.

It is a self number, because there is not a number n which added to its sum of digits gives 81937968.

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, 121596 + ... + 122267.

Almost surely, 2^81937968 is an apocalyptic number.

It is an amenable number.

81937968 is an abundant number, since it is smaller than the sum of its proper divisors (159975120).

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

81937968 is a wasteful number, since it uses less digits than its factorization.

81937968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243881 (or 243875 counting only the distinct ones).

The product of its digits is 653184, while the sum is 51.

The square root of 81937968 is about 9051.9593459096. The cubic root of 81937968 is about 434.3385693650.

It can be divided in two parts, 8193 and 7968, that added together give a palindrome (16161).

The spelling of 81937968 in words is "eighty-one million, nine hundred thirty-seven thousand, nine hundred sixty-eight".