81573620025 has 12 divisors (see below), whose sum is σ = 134868385232. Its totient is φ = 43505930640.

The previous prime is 81573620003. The next prime is 81573620027. The reversal of 81573620025 is 52002637518.

It is not a de Polignac number, because 81573620025 - 2⁵ = 81573619993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81573620027) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 543824059 + ... + 543824208.

Almost surely, 2^81573620025 is an apocalyptic number.

It is an amenable number.

81573620025 is a deficient number, since it is larger than the sum of its proper divisors (53294765207).

81573620025 is a wasteful number, since it uses less digits than its factorization.

81573620025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1087648280 (or 1087648275 counting only the distinct ones).

The product of its (nonzero) digits is 100800, while the sum is 39.

The spelling of 81573620025 in words is "eighty-one billion, five hundred seventy-three million, six hundred twenty thousand, twenty-five".