668780020 has 36 divisors (see below), whose sum is σ = 1454573484. Its totient is φ = 258280960.

The previous prime is 668780003. The next prime is 668780071. The reversal of 668780020 is 20087866.

It can be written as a sum of positive squares in 6 ways, for example, as 55920484 + 612859536 = 7478^2 + 24756^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3061 + ... + 36700.

It is an arithmetic number, because the mean of its divisors is an integer number (40404819).

Almost surely, 2^668780020 is an apocalyptic number.

It is an amenable number.

668780020 is an abundant number, since it is smaller than the sum of its proper divisors (785793464).

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

668780020 is a wasteful number, since it uses less digits than its factorization.

668780020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39828 (or 39797 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 37.

The square root of 668780020 is about 25860.7815040459. The cubic root of 668780020 is about 874.5025831342.

The spelling of 668780020 in words is "six hundred sixty-eight million, seven hundred eighty thousand, twenty".