669680820 has 72 divisors (see below), whose sum is σ = 2034415656. Its totient is φ = 178313472.

The previous prime is 669680771. The next prime is 669680833. The reversal of 669680820 is 28086966.

669680820 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 23097636 + 646583184 = 4806^2 + 25428^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 136734 + ... + 141546.

It is an arithmetic number, because the mean of its divisors is an integer number (28255773).

Almost surely, 2^669680820 is an apocalyptic number.

669680820 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

669680820 is an abundant number, since it is smaller than the sum of its proper divisors (1364734836).

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

669680820 is a wasteful number, since it uses less digits than its factorization.

669680820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5601 (or 5596 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The square root of 669680820 is about 25878.1919770296. The cubic root of 669680820 is about 874.8950382940.

The spelling of 669680820 in words is "six hundred sixty-nine million, six hundred eighty thousand, eight hundred twenty".