6611565051521 has 2 divisors, whose sum is σ = 6611565051522. Its totient is φ = 6611565051520.

The previous prime is 6611565051517. The next prime is 6611565051529. The reversal of 6611565051521 is 1251505651166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3924899850496 + 2686665201025 = 1981136^2 + 1639105^2 .

It is a cyclic number.

It is not a de Polignac number, because 6611565051521 - 2² = 6611565051517 is a prime.

It is not a weakly prime, because it can be changed into another prime (6611565051529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3305782525760 + 3305782525761.

It is an arithmetic number, because the mean of its divisors is an integer number (3305782525761).

Almost surely, 2^{6611565051521} is an apocalyptic number.

It is an amenable number.

6611565051521 is a deficient number, since it is larger than the sum of its proper divisors (1).

6611565051521 is an equidigital number, since it uses as much as digits as its factorization.

6611565051521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 270000, while the sum is 44.

The spelling of 6611565051521 in words is "six trillion, six hundred eleven billion, five hundred sixty-five million, fifty-one thousand, five hundred twenty-one".