668957 has 4 divisors (see below), whose sum is σ = 670716. Its totient is φ = 667200.

The previous prime is 668947. The next prime is 668959. The reversal of 668957 is 759866.

It is a happy number.

668957 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19321 + 649636 = 139^2 + 806^2 .

It is a cyclic number.

It is not a de Polignac number, because 668957 - 2¹⁴ = 652573 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668959) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44 + ... + 1157.

It is an arithmetic number, because the mean of its divisors is an integer number (167679).

2⁶⁶⁸⁹⁵⁷ is an apocalyptic number.

It is an amenable number.

668957 is a deficient number, since it is larger than the sum of its proper divisors (1759).

668957 is a wasteful number, since it uses less digits than its factorization.

668957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1758.

The product of its digits is 90720, while the sum is 41.

The square root of 668957 is about 817.8979153904. The cubic root of 668957 is about 87.4579716527.

Subtracting 668957 from its reverse (759866), we obtain a palindrome (90909).

The spelling of 668957 in words is "six hundred sixty-eight thousand, nine hundred fifty-seven".