2660136666521 has 2 divisors, whose sum is σ = 2660136666522. Its totient is φ = 2660136666520.

The previous prime is 2660136666427. The next prime is 2660136666529. The reversal of 2660136666521 is 1256666310662.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1915995798025 + 744140868496 = 1384195^2 + 862636^2 .

It is a cyclic number.

It is not a de Polignac number, because 2660136666521 - 2³⁴ = 2642956797337 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 2660136666521.

It is not a weakly prime, because it can be changed into another prime (2660136666529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1330068333260 + 1330068333261.

It is an arithmetic number, because the mean of its divisors is an integer number (1330068333261).

Almost surely, 2^{2660136666521} is an apocalyptic number.

It is an amenable number.

2660136666521 is a deficient number, since it is larger than the sum of its proper divisors (1).

2660136666521 is an equidigital number, since it uses as much as digits as its factorization.

2660136666521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2799360, while the sum is 50.

The spelling of 2660136666521 in words is "two trillion, six hundred sixty billion, one hundred thirty-six million, six hundred sixty-six thousand, five hundred twenty-one".