668597957 has 2 divisors, whose sum is σ = 668597958. Its totient is φ = 668597956.

The previous prime is 668597939. The next prime is 668597989. The reversal of 668597957 is 759795866.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 659513761 + 9084196 = 25681^2 + 3014^2 .

It is a cyclic number.

It is not a de Polignac number, because 668597957 - 2²⁶ = 601489093 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 668597957.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668597357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334298978 + 334298979.

It is an arithmetic number, because the mean of its divisors is an integer number (334298979).

Almost surely, 2^668597957 is an apocalyptic number.

It is an amenable number.

668597957 is a deficient number, since it is larger than the sum of its proper divisors (1).

668597957 is an equidigital number, since it uses as much as digits as its factorization.

668597957 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28576800, while the sum is 62.

The square root of 668597957 is about 25857.2612045437. The cubic root of 668597957 is about 874.4232202102.

The spelling of 668597957 in words is "six hundred sixty-eight million, five hundred ninety-seven thousand, nine hundred fifty-seven".