664767 has 20 divisors (see below), whose sum is σ = 1030920. Its totient is φ = 426384.

The previous prime is 664757. The next prime is 664771. The reversal of 664767 is 767466.

664767 is a `hidden beast` number, since 6 + 647 + 6 + 7 = 666.

It is not a de Polignac number, because 664767 - 2⁸ = 664511 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is an Ulam number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 664767.

It is not an unprimeable number, because it can be changed into a prime (664757) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 2208 + ... + 2490.

It is an arithmetic number, because the mean of its divisors is an integer number (51546).

2⁶⁶⁴⁷⁶⁷ is an apocalyptic number.

664767 is a deficient number, since it is larger than the sum of its proper divisors (366153).

664767 is a wasteful number, since it uses less digits than its factorization.

664767 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 324 (or 315 counting only the distinct ones).

The product of its digits is 42336, while the sum is 36.

The square root of 664767 is about 815.3324475329. The cubic root of 664767 is about 87.2749919512.

It can be divided in two parts, 664 and 767, that added together give a triangular number (1431 = T₅₃).

The spelling of 664767 in words is "six hundred sixty-four thousand, seven hundred sixty-seven".