81948728 has 8 divisors (see below), whose sum is σ = 153653880. Its totient is φ = 40974360.

The previous prime is 81948677. The next prime is 81948731. The reversal of 81948728 is 82784918.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5121788 + ... + 5121803.

It is an arithmetic number, because the mean of its divisors is an integer number (19206735).

Almost surely, 2^81948728 is an apocalyptic number.

It is an amenable number.

81948728 is a deficient number, since it is larger than the sum of its proper divisors (71705152).

81948728 is a wasteful number, since it uses less digits than its factorization.

81948728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10243597 (or 10243593 counting only the distinct ones).

The product of its digits is 258048, while the sum is 47.

The square root of 81948728 is about 9052.5536728594. The cubic root of 81948728 is about 434.3575808138.

The spelling of 81948728 in words is "eighty-one million, nine hundred forty-eight thousand, seven hundred twenty-eight".