81660512504601 has 12 divisors (see below), whose sum is σ = 117990739520212. Its totient is φ = 54423418945536.

The previous prime is 81660512504569. The next prime is 81660512504621. The reversal of 81660512504601 is 10640521506618.

81660512504601 is a `hidden beast` number, since 8 + 1 + 6 + 60 + 5 + 125 + 0 + 460 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 38070134010000 + 43590378494601 = 6170100^2 + 6602301^2 .

It is not a de Polignac number, because 81660512504601 - 2⁵ = 81660512504569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81660512504621) 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, 1410196456 + ... + 1410254361.

Almost surely, 2^{81660512504601} is an apocalyptic number.

It is an amenable number.

81660512504601 is a deficient number, since it is larger than the sum of its proper divisors (36330227015611).

81660512504601 is a wasteful number, since it uses less digits than its factorization.

81660512504601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2820454040 (or 2820454037 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 45.

The spelling of 81660512504601 in words is "eighty-one trillion, six hundred sixty billion, five hundred twelve million, five hundred four thousand, six hundred one".