668257 has 4 divisors (see below), whose sum is σ = 686356. Its totient is φ = 650160.

The previous prime is 668243. The next prime is 668273. The reversal of 668257 is 752866.

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 571536 + 96721 = 756^2 + 311^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-668257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (618257) 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, 8994 + ... + 9067.

It is an arithmetic number, because the mean of its divisors is an integer number (171589).

2⁶⁶⁸²⁵⁷ is an apocalyptic number.

It is an amenable number.

668257 is a deficient number, since it is larger than the sum of its proper divisors (18099).

668257 is a wasteful number, since it uses less digits than its factorization.

668257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18098.

The product of its digits is 20160, while the sum is 34.

The square root of 668257 is about 817.4698771209. The cubic root of 668257 is about 87.4274555177.

The spelling of 668257 in words is "six hundred sixty-eight thousand, two hundred fifty-seven".