669646780 has 24 divisors (see below), whose sum is σ = 1534100400. Its totient is φ = 243507840.

The previous prime is 669646777. The next prime is 669646781. The reversal of 669646780 is 87646966.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669646781) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1521705 + ... + 1522144.

It is an arithmetic number, because the mean of its divisors is an integer number (63920850).

Almost surely, 2^669646780 is an apocalyptic number.

It is an amenable number.

669646780 is an abundant number, since it is smaller than the sum of its proper divisors (864453620).

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

669646780 is a wasteful number, since it uses less digits than its factorization.

669646780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3043869 (or 3043867 counting only the distinct ones).

The product of its (nonzero) digits is 2612736, while the sum is 52.

The square root of 669646780 is about 25877.5342720283. The cubic root of 669646780 is about 874.8802143506.

The spelling of 669646780 in words is "six hundred sixty-nine million, six hundred forty-six thousand, seven hundred eighty".