66500061016661 has 2 divisors, whose sum is σ = 66500061016662. Its totient is φ = 66500061016660.

The previous prime is 66500061016651. The next prime is 66500061016667. The reversal of 66500061016661 is 16661016000566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 46852916116561 + 19647144900100 = 6844919^2 + 4432510^2 .

It is a cyclic number.

It is not a de Polignac number, because 66500061016661 - 2²⁶ = 66499993907797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66500061016667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33250030508330 + 33250030508331.

It is an arithmetic number, because the mean of its divisors is an integer number (33250030508331).

Almost surely, 2^{66500061016661} is an apocalyptic number.

It is an amenable number.

66500061016661 is a deficient number, since it is larger than the sum of its proper divisors (1).

66500061016661 is an equidigital number, since it uses as much as digits as its factorization.

66500061016661 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 44.

It can be divided in two parts, 6650006 and 1016661, that added together give a palindrome (7666667).

The spelling of 66500061016661 in words is "sixty-six trillion, five hundred billion, sixty-one million, sixteen thousand, six hundred sixty-one".