664785 has 48 divisors (see below), whose sum is σ = 1347840. Its totient is φ = 299520.

The previous prime is 664777. The next prime is 664789. The reversal of 664785 is 587466.

664785 = 49³ + 50³ + ... + 53³.

It is a happy number.

664785 is a `hidden beast` number, since 6 + 647 + 8 + 5 = 666.

664785 is digitally balanced in base 7, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 664785 - 2³ = 664777 is a prime.

664785 is strictly pandigital in base 7.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 664785.

It is not an unprimeable number, because it can be changed into a prime (664789) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 8376 + ... + 8454.

It is an arithmetic number, because the mean of its divisors is an integer number (28080).

2⁶⁶⁴⁷⁸⁵ is an apocalyptic number.

It is an amenable number.

664785 is an abundant number, since it is smaller than the sum of its proper divisors (683055).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

664785 is a wasteful number, since it uses less digits than its factorization.

664785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118 (or 115 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 664785 is about 815.3434859003. The cubic root of 664785 is about 87.2757796636.

It can be divided in two parts, 66 and 4785, that added together give a triangular number (4851 = T₉₈).

The spelling of 664785 in words is "six hundred sixty-four thousand, seven hundred eighty-five".