6666555611501 has 2 divisors, whose sum is σ = 6666555611502. Its totient is φ = 6666555611500.

The previous prime is 6666555611491. The next prime is 6666555611539. The reversal of 6666555611501 is 1051165556666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4642736399401 + 2023819212100 = 2154701^2 + 1422610^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6666555611501 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6666555611591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3333277805750 + 3333277805751.

It is an arithmetic number, because the mean of its divisors is an integer number (3333277805751).

Almost surely, 2^{6666555611501} is an apocalyptic number.

It is an amenable number.

6666555611501 is a deficient number, since it is larger than the sum of its proper divisors (1).

6666555611501 is an equidigital number, since it uses as much as digits as its factorization.

6666555611501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4860000, while the sum is 53.

The spelling of 6666555611501 in words is "six trillion, six hundred sixty-six billion, five hundred fifty-five million, six hundred eleven thousand, five hundred one".