81237928 has 8 divisors (see below), whose sum is σ = 152321130. Its totient is φ = 40618960.

The previous prime is 81237913. The next prime is 81237973. The reversal of 81237928 is 82973218.

It can be written as a sum of positive squares in only one way, i.e., 52099524 + 29138404 = 7218^2 + 5398^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5077363 + ... + 5077378.

Almost surely, 2^81237928 is an apocalyptic number.

It is an amenable number.

81237928 is a deficient number, since it is larger than the sum of its proper divisors (71083202).

81237928 is a wasteful number, since it uses less digits than its factorization.

81237928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10154747 (or 10154743 counting only the distinct ones).

The product of its digits is 48384, while the sum is 40.

The square root of 81237928 is about 9013.2085297079. The cubic root of 81237928 is about 433.0981008624.

The spelling of 81237928 in words is "eighty-one million, two hundred thirty-seven thousand, nine hundred twenty-eight".