66644844569 has 2 divisors, whose sum is σ = 66644844570. Its totient is φ = 66644844568.

The previous prime is 66644844529. The next prime is 66644844743. The reversal of 66644844569 is 96544844666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 59432588944 + 7212255625 = 243788^2 + 84925^2 .

It is a cyclic number.

It is not a de Polignac number, because 66644844569 - 2²⁰ = 66643795993 is a prime.

It is a super-2 number, since 2×66644844569² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66644844509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33322422284 + 33322422285.

It is an arithmetic number, because the mean of its divisors is an integer number (33322422285).

Almost surely, 2^66644844569 is an apocalyptic number.

It is an amenable number.

66644844569 is a deficient number, since it is larger than the sum of its proper divisors (1).

66644844569 is an equidigital number, since it uses as much as digits as its factorization.

66644844569 is an evil number, because the sum of its binary digits is even.

The product of its digits is 119439360, while the sum is 62.

The spelling of 66644844569 in words is "sixty-six billion, six hundred forty-four million, eight hundred forty-four thousand, five hundred sixty-nine".