660664 has 16 divisors (see below), whose sum is σ = 1247400. Its totient is φ = 328032.

The previous prime is 660661. The next prime is 660683. The reversal of 660664 is 466066.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1999 + ... + 2305.

2⁶⁶⁰⁶⁶⁴ is an apocalyptic number.

It is an amenable number.

660664 is a deficient number, since it is larger than the sum of its proper divisors (586736).

660664 is a wasteful number, since it uses less digits than its factorization.

660664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 582 (or 578 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 28.

The square root of 660664 is about 812.8124014802. The cubic root of 660664 is about 87.0950649752.

It can be divided in two parts, 6606 and 64, that added together give a triangular number (6670 = T₁₁₅).

The spelling of 660664 in words is "six hundred sixty thousand, six hundred sixty-four".