667657 has 2 divisors, whose sum is σ = 667658. Its totient is φ = 667656.

The previous prime is 667649. The next prime is 667673. The reversal of 667657 is 756766.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 456976 + 210681 = 676^2 + 459^2 .

It is a cyclic number.

It is not a de Polignac number, because 667657 - 2³ = 667649 is a prime.

It is a Chen prime.

It is an Ulam number.

It is not a weakly prime, because it can be changed into another prime (667687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333828 + 333829.

It is an arithmetic number, because the mean of its divisors is an integer number (333829).

2⁶⁶⁷⁶⁵⁷ is an apocalyptic number.

It is an amenable number.

667657 is a deficient number, since it is larger than the sum of its proper divisors (1).

667657 is an equidigital number, since it uses as much as digits as its factorization.

667657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 52920, while the sum is 37.

The square root of 667657 is about 817.1028087089. The cubic root of 667657 is about 87.4012818646.

The spelling of 667657 in words is "six hundred sixty-seven thousand, six hundred fifty-seven".