66567145681 has 2 divisors, whose sum is σ = 66567145682. Its totient is φ = 66567145680.

The previous prime is 66567145621. The next prime is 66567145691. The reversal of 66567145681 is 18654176566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63413312400 + 3153833281 = 251820^2 + 56159^2 .

It is a cyclic number.

It is not a de Polignac number, because 66567145681 - 2⁷ = 66567145553 is a prime.

It is a super-2 number, since 2×66567145681² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66567145621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33283572840 + 33283572841.

It is an arithmetic number, because the mean of its divisors is an integer number (33283572841).

Almost surely, 2^66567145681 is an apocalyptic number.

It is an amenable number.

66567145681 is a deficient number, since it is larger than the sum of its proper divisors (1).

66567145681 is an equidigital number, since it uses as much as digits as its factorization.

66567145681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7257600, while the sum is 55.

The spelling of 66567145681 in words is "sixty-six billion, five hundred sixty-seven million, one hundred forty-five thousand, six hundred eighty-one".