669639636 has 30 divisors (see below), whose sum is σ = 1750571130. Its totient is φ = 223213104.

The previous prime is 669639613. The next prime is 669639671. The reversal of 669639636 is 636936966.

It can be written as a sum of positive squares in only one way, i.e., 626000400 + 43639236 = 25020^2 + 6606^2 .

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1033071 + ... + 1033718.

It is an arithmetic number, because the mean of its divisors is an integer number (58352371).

Almost surely, 2^669639636 is an apocalyptic number.

It is an amenable number.

669639636 is an abundant number, since it is smaller than the sum of its proper divisors (1080931494).

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

669639636 is a wasteful number, since it uses less digits than its factorization.

669639636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2066805 (or 2066794 counting only the distinct ones).

The product of its digits is 5668704, while the sum is 54.

The square root of 669639636 is about 25877.3962368705. The cubic root of 669639636 is about 874.8771031749.

The spelling of 669639636 in words is "six hundred sixty-nine million, six hundred thirty-nine thousand, six hundred thirty-six".