664965 has 24 divisors (see below), whose sum is σ = 1317888. Its totient is φ = 303840.

The previous prime is 664949. The next prime is 664967. The reversal of 664965 is 569466.

It is a happy number.

664965 is a `hidden beast` number, since 6 + 649 + 6 + 5 = 666.

It is not a de Polignac number, because 664965 - 2⁴ = 664949 is a prime.

It is an Ulam number.

664965 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664967) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 741 + ... + 1370.

It is an arithmetic number, because the mean of its divisors is an integer number (54912).

2⁶⁶⁴⁹⁶⁵ is an apocalyptic number.

It is an amenable number.

664965 is a deficient number, since it is larger than the sum of its proper divisors (652923).

664965 is a wasteful number, since it uses less digits than its factorization.

664965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2129 (or 2126 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 664965 is about 815.4538613557. The cubic root of 664965 is about 87.2836560059.

The spelling of 664965 in words is "six hundred sixty-four thousand, nine hundred sixty-five".