669989980 has 72 divisors (see below), whose sum is σ = 1586496240. Its totient is φ = 235699200.

The previous prime is 669989933. The next prime is 669989981. The reversal of 669989980 is 89989966.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669989981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 209836 + ... + 213004.

It is an arithmetic number, because the mean of its divisors is an integer number (22034670).

Almost surely, 2^669989980 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 669989980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (793248120).

669989980 is an abundant number, since it is smaller than the sum of its proper divisors (916506260).

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

669989980 is a wasteful number, since it uses less digits than its factorization.

669989980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3251 (or 3218 counting only the distinct ones).

The product of its (nonzero) digits is 15116544, while the sum is 64.

The square root of 669989980 is about 25884.1646571799. The cubic root of 669989980 is about 875.0296501517.

The spelling of 669989980 in words is "six hundred sixty-nine million, nine hundred eighty-nine thousand, nine hundred eighty".