669585728 has 56 divisors (see below), whose sum is σ = 1522975872. Its totient is φ = 286124544.

The previous prime is 669585701. The next prime is 669585731. The reversal of 669585728 is 827585966.

It is a tau number, because it is divible by the number of its divisors (56).

It is a Harshad number since it is a multiple of its sum of digits (56).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 165101 + ... + 169107.

Almost surely, 2^669585728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 669585728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (761487936).

669585728 is an abundant number, since it is smaller than the sum of its proper divisors (853390144).

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

669585728 is a wasteful number, since it uses less digits than its factorization.

669585728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4399 (or 4389 counting only the distinct ones).

The product of its digits is 7257600, while the sum is 56.

The square root of 669585728 is about 25876.3546118846. The cubic root of 669585728 is about 874.8536258009.

The spelling of 669585728 in words is "six hundred sixty-nine million, five hundred eighty-five thousand, seven hundred twenty-eight".