81625728475 has 24 divisors (see below), whose sum is σ = 101778003152. Its totient is φ = 64938931200.

The previous prime is 81625728467. The next prime is 81625728521. The reversal of 81625728475 is 57482752618.

It is not a de Polignac number, because 81625728475 - 2³ = 81625728467 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3376180 + ... + 3400270.

Almost surely, 2^81625728475 is an apocalyptic number.

81625728475 is a deficient number, since it is larger than the sum of its proper divisors (20152274677).

81625728475 is a wasteful number, since it uses less digits than its factorization.

81625728475 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24847 (or 24842 counting only the distinct ones).

The product of its digits is 7526400, while the sum is 55.

The spelling of 81625728475 in words is "eighty-one billion, six hundred twenty-five million, seven hundred twenty-eight thousand, four hundred seventy-five".