12520716665 has 32 divisors (see below), whose sum is σ = 16002502560. Its totient is φ = 9371971584.

The previous prime is 12520716623. The next prime is 12520716673. The reversal of 12520716665 is 56661702521.

It can be written as a sum of positive squares in 16 ways, for example, as 5719745641 + 6800971024 = 75629^2 + 82468^2 .

It is a cyclic number.

It is not a de Polignac number, because 12520716665 - 2⁸ = 12520716409 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 17659331 + ... + 17660039.

It is an arithmetic number, because the mean of its divisors is an integer number (500078205).

Almost surely, 2^12520716665 is an apocalyptic number.

It is an amenable number.

12520716665 is a deficient number, since it is larger than the sum of its proper divisors (3481785895).

12520716665 is a wasteful number, since it uses less digits than its factorization.

12520716665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1661.

The product of its (nonzero) digits is 151200, while the sum is 41.

The spelling of 12520716665 in words is "twelve billion, five hundred twenty million, seven hundred sixteen thousand, six hundred sixty-five".