81241928 has 8 divisors (see below), whose sum is σ = 152328630. Its totient is φ = 40620960.

The previous prime is 81241907. The next prime is 81241931. The reversal of 81241928 is 82914218.

It can be written as a sum of positive squares in only one way, i.e., 59320804 + 21921124 = 7702^2 + 4682^2 .

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, 5077613 + ... + 5077628.

Almost surely, 2^81241928 is an apocalyptic number.

It is an amenable number.

81241928 is a deficient number, since it is larger than the sum of its proper divisors (71086702).

81241928 is a wasteful number, since it uses less digits than its factorization.

81241928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10155247 (or 10155243 counting only the distinct ones).

The product of its digits is 9216, while the sum is 35.

The square root of 81241928 is about 9013.4304235402. The cubic root of 81241928 is about 433.1052090528.

The spelling of 81241928 in words is "eighty-one million, two hundred forty-one thousand, nine hundred twenty-eight".