81957956089 has 9 divisors (see below), whose sum is σ = 82292259279. Its totient is φ = 81625008960.

The previous prime is 81957956083. The next prime is 81957956123. The reversal of 81957956089 is 98065975918.

The square root of 81957956089 is 286283.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 33297125625 + 48660830464 = 182475^2 + 220592^2 .

It is not a de Polignac number, because 81957956089 - 2¹¹ = 81957954041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81957956083) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 101057494 + ... + 101058304.

Almost surely, 2^81957956089 is an apocalyptic number.

81957956089 is the 286283-rd square number.

81957956089 is the 143142-nd centered octagonal number.

It is an amenable number.

81957956089 is a deficient number, since it is larger than the sum of its proper divisors (334303190).

81957956089 is an frugal number, since it uses more digits than its factorization.

81957956089 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2328 (or 1164 counting only the distinct ones).

The product of its (nonzero) digits is 48988800, while the sum is 67.

The spelling of 81957956089 in words is "eighty-one billion, nine hundred fifty-seven million, nine hundred fifty-six thousand, eighty-nine".