66568466486581 has 2 divisors, whose sum is σ = 66568466486582. Its totient is φ = 66568466486580.

The previous prime is 66568466486531. The next prime is 66568466486659. The reversal of 66568466486581 is 18568466486566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51572721402225 + 14995745084356 = 7181415^2 + 3872434^2 .

It is a cyclic number.

It is not a de Polignac number, because 66568466486581 - 2²⁹ = 66567929615669 is a prime.

It is a super-2 number, since 2×66568466486581² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66568466486531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33284233243290 + 33284233243291.

It is an arithmetic number, because the mean of its divisors is an integer number (33284233243291).

Almost surely, 2^{66568466486581} is an apocalyptic number.

It is an amenable number.

66568466486581 is a deficient number, since it is larger than the sum of its proper divisors (1).

66568466486581 is an equidigital number, since it uses as much as digits as its factorization.

66568466486581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9555148800, while the sum is 79.

The spelling of 66568466486581 in words is "sixty-six trillion, five hundred sixty-eight billion, four hundred sixty-six million, four hundred eighty-six thousand, five hundred eighty-one".