656666444404489 has 2 divisors, whose sum is σ = 656666444404490. Its totient is φ = 656666444404488.

The previous prime is 656666444404403. The next prime is 656666444404513. The reversal of 656666444404489 is 984404444666656.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 558846432244489 + 97820012160000 = 23639933^2 + 9890400^2 .

It is a cyclic number.

It is not a de Polignac number, because 656666444404489 - 2¹⁷ = 656666444273417 is a prime.

It is a super-2 number, since 2×656666444404489² (a number of 30 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (656666444401489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328333222202244 + 328333222202245.

It is an arithmetic number, because the mean of its divisors is an integer number (328333222202245).

Almost surely, 2^{656666444404489} is an apocalyptic number.

It is an amenable number.

656666444404489 is a deficient number, since it is larger than the sum of its proper divisors (1).

656666444404489 is an equidigital number, since it uses as much as digits as its factorization.

656666444404489 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11466178560, while the sum is 76.

The spelling of 656666444404489 in words is "six hundred fifty-six trillion, six hundred sixty-six billion, four hundred forty-four million, four hundred four thousand, four hundred eighty-nine".