81059180657 has 12 divisors (see below), whose sum is σ = 101546666676. Its totient is φ = 64134735840.

The previous prime is 81059180641. The next prime is 81059180677. The reversal of 81059180657 is 75608195018.

It can be written as a sum of positive squares in 2 ways, for example, as 47174102416 + 33885078241 = 217196^2 + 184079^2 .

It is not a de Polignac number, because 81059180657 - 2⁴ = 81059180641 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81059180627) 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, 63625094 + ... + 63626367.

It is an arithmetic number, because the mean of its divisors is an integer number (8462222223).

Almost surely, 2^81059180657 is an apocalyptic number.

It is an amenable number.

81059180657 is a deficient number, since it is larger than the sum of its proper divisors (20487486019).

81059180657 is a wasteful number, since it uses less digits than its factorization.

81059180657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127251488 (or 127251481 counting only the distinct ones).

The product of its (nonzero) digits is 604800, while the sum is 50.

The spelling of 81059180657 in words is "eighty-one billion, fifty-nine million, one hundred eighty thousand, six hundred fifty-seven".