664657 has 4 divisors (see below), whose sum is σ = 759616. Its totient is φ = 569700.

The previous prime is 664633. The next prime is 664661. The reversal of 664657 is 756466.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 664657 - 2⁷ = 664529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47469 + ... + 47482.

It is an arithmetic number, because the mean of its divisors is an integer number (189904).

2⁶⁶⁴⁶⁵⁷ is an apocalyptic number.

It is an amenable number.

664657 is a deficient number, since it is larger than the sum of its proper divisors (94959).

664657 is an equidigital number, since it uses as much as digits as its factorization.

664657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94958.

The product of its digits is 30240, while the sum is 34.

The square root of 664657 is about 815.2649875961. The cubic root of 664657 is about 87.2701778440.

Subtracting 664657 from its reverse (756466), we obtain a square (91809 = 303²).

The spelling of 664657 in words is "six hundred sixty-four thousand, six hundred fifty-seven".