669775644 has 18 divisors (see below), whose sum is σ = 1693044080. Its totient is φ = 223258536.

The previous prime is 669775637. The next prime is 669775651. The reversal of 669775644 is 446577966.

669775644 is a `hidden beast` number, since 6 + 6 + 9 + 77 + 564 + 4 = 666.

It is an interprime number because it is at equal distance from previous prime (669775637) and next prime (669775651).

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×669775644² = 897198826591229472, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9302404 + ... + 9302475.

Almost surely, 2^669775644 is an apocalyptic number.

It is an amenable number.

669775644 is an abundant number, since it is smaller than the sum of its proper divisors (1023268436).

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

669775644 is a wasteful number, since it uses less digits than its factorization.

669775644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18604889 (or 18604884 counting only the distinct ones).

The product of its digits is 7620480, while the sum is 54.

The square root of 669775644 is about 25880.0240339919. The cubic root of 669775644 is about 874.9363301699.

The spelling of 669775644 in words is "six hundred sixty-nine million, seven hundred seventy-five thousand, six hundred forty-four".