669643056 has 90 divisors (see below), whose sum is σ = 1990918332. Its totient is φ = 210071040.

The previous prime is 669643043. The next prime is 669643061. The reversal of 669643056 is 650346966.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 33571 + ... + 49661.

Almost surely, 2^669643056 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 669643056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (995459166).

669643056 is an abundant number, since it is smaller than the sum of its proper divisors (1321275276).

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

669643056 is a wasteful number, since it uses less digits than its factorization.

669643056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16139 (or 16113 counting only the distinct ones).

The product of its (nonzero) digits is 699840, while the sum is 45.

The square root of 669643056 is about 25877.4623176230. The cubic root of 669643056 is about 874.8785925703.

The spelling of 669643056 in words is "six hundred sixty-nine million, six hundred forty-three thousand, fifty-six".