21660100656613 has 2 divisors, whose sum is σ = 21660100656614. Its totient is φ = 21660100656612.

The previous prime is 21660100656553. The next prime is 21660100656659. The reversal of 21660100656613 is 31665600106612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20736566202564 + 923534454049 = 4553742^2 + 961007^2 .

It is a cyclic number.

It is not a de Polignac number, because 21660100656613 - 2⁴¹ = 19461077401061 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21660100656613.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21660100656683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10830050328306 + 10830050328307.

It is an arithmetic number, because the mean of its divisors is an integer number (10830050328307).

Almost surely, 2^{21660100656613} is an apocalyptic number.

It is an amenable number.

21660100656613 is a deficient number, since it is larger than the sum of its proper divisors (1).

21660100656613 is an equidigital number, since it uses as much as digits as its factorization.

21660100656613 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 233280, while the sum is 43.

The spelling of 21660100656613 in words is "twenty-one trillion, six hundred sixty billion, one hundred million, six hundred fifty-six thousand, six hundred thirteen".