668754686657 has 2 divisors, whose sum is σ = 668754686658. Its totient is φ = 668754686656.

The previous prime is 668754686599. The next prime is 668754686693. The reversal of 668754686657 is 756686457866.

668754686657 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 368274204736 + 300480481921 = 606856^2 + 548161^2 .

It is a cyclic number.

It is not a de Polignac number, because 668754686657 - 2²² = 668750492353 is a prime.

It is not a weakly prime, because it can be changed into another prime (668754682657) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334377343328 + 334377343329.

It is an arithmetic number, because the mean of its divisors is an integer number (334377343329).

Almost surely, 2^668754686657 is an apocalyptic number.

It is an amenable number.

668754686657 is a deficient number, since it is larger than the sum of its proper divisors (1).

668754686657 is an equidigital number, since it uses as much as digits as its factorization.

668754686657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2438553600, while the sum is 74.

The spelling of 668754686657 in words is "six hundred sixty-eight billion, seven hundred fifty-four million, six hundred eighty-six thousand, six hundred fifty-seven".