667664 has 10 divisors (see below), whose sum is σ = 1293630. Its totient is φ = 333824.

The previous prime is 667657. The next prime is 667673. The reversal of 667664 is 466766.

It can be written as a sum of positive squares in only one way, i.e., 409600 + 258064 = 640^2 + 508^2 .

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 667664.

It is an unprimeable number.

667664 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20849 + ... + 20880.

It is an arithmetic number, because the mean of its divisors is an integer number (129363).

2⁶⁶⁷⁶⁶⁴ is an apocalyptic number.

It is an amenable number.

667664 is a deficient number, since it is larger than the sum of its proper divisors (625966).

667664 is a wasteful number, since it uses less digits than its factorization.

667664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41737 (or 41731 counting only the distinct ones).

The product of its digits is 36288, while the sum is 35.

The square root of 667664 is about 817.1070921244. The cubic root of 667664 is about 87.4015873143.

It can be divided in two parts, 667 and 664, that added together give a palindrome (1331).

The spelling of 667664 in words is "six hundred sixty-seven thousand, six hundred sixty-four".