664897 has 4 divisors (see below), whose sum is σ = 681156. Its totient is φ = 648640.

The previous prime is 664891. The next prime is 664933. The reversal of 664897 is 798466.

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 254016 + 410881 = 504^2 + 641^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-664897 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (664891) 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, 8068 + ... + 8149.

It is an arithmetic number, because the mean of its divisors is an integer number (170289).

2⁶⁶⁴⁸⁹⁷ is an apocalyptic number.

It is an amenable number.

664897 is a deficient number, since it is larger than the sum of its proper divisors (16259).

664897 is a wasteful number, since it uses less digits than its factorization.

664897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16258.

The product of its digits is 72576, while the sum is 40.

The square root of 664897 is about 815.4121657174. The cubic root of 664897 is about 87.2806806659.

The spelling of 664897 in words is "six hundred sixty-four thousand, eight hundred ninety-seven".