664786 has 4 divisors (see below), whose sum is σ = 997182. Its totient is φ = 332392.

The previous prime is 664777. The next prime is 664789. The reversal of 664786 is 687466.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 632025 + 32761 = 795^2 + 181^2 .

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 as a sum of consecutive naturals, namely, 166195 + ... + 166198.

2⁶⁶⁴⁷⁸⁶ is an apocalyptic number.

664786 is a deficient number, since it is larger than the sum of its proper divisors (332396).

664786 is a wasteful number, since it uses less digits than its factorization.

664786 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332395.

The product of its digits is 48384, while the sum is 37.

The square root of 664786 is about 815.3440991385. The cubic root of 664786 is about 87.2758234250.

The spelling of 664786 in words is "six hundred sixty-four thousand, seven hundred eighty-six".