664769 has 8 divisors (see below), whose sum is σ = 792960. Its totient is φ = 544896.

The previous prime is 664757. The next prime is 664771. The reversal of 664769 is 967466.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-664769 is a prime.

It is a super-2 number, since 2×664769² = 883835646722, which contains 22 as substring.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (664739) 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 7 ways as a sum of consecutive naturals, for example, 1904 + ... + 2225.

It is an arithmetic number, because the mean of its divisors is an integer number (99120).

2⁶⁶⁴⁷⁶⁹ is an apocalyptic number.

It is an amenable number.

664769 is a deficient number, since it is larger than the sum of its proper divisors (128191).

664769 is a wasteful number, since it uses less digits than its factorization.

664769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4159.

The product of its digits is 54432, while the sum is 38.

The square root of 664769 is about 815.3336740255. Note that the first 3 decimals coincide. The cubic root of 664769 is about 87.2750794755.

The spelling of 664769 in words is "six hundred sixty-four thousand, seven hundred sixty-nine".