669564 has 36 divisors (see below), whose sum is σ = 1935024. Its totient is φ = 191232.

The previous prime is 669551. The next prime is 669577. The reversal of 669564 is 465966.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (669551) and next prime (669577).

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1077 + ... + 1580.

2⁶⁶⁹⁵⁶⁴ is an apocalyptic number.

It is an amenable number.

669564 is an abundant number, since it is smaller than the sum of its proper divisors (1265460).

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

669564 is a wasteful number, since it uses less digits than its factorization.

669564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2674 (or 2669 counting only the distinct ones).

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

The square root of 669564 is about 818.2689044562. The cubic root of 669564 is about 87.4844162723.

The spelling of 669564 in words is "six hundred sixty-nine thousand, five hundred sixty-four".