668578420 has 12 divisors (see below), whose sum is σ = 1404014724. Its totient is φ = 267431360.

The previous prime is 668578381. The next prime is 668578439. The reversal of 668578420 is 24875866.

It can be written as a sum of positive squares in 2 ways, for example, as 345513744 + 323064676 = 18588^2 + 17974^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16714441 + ... + 16714480.

It is an arithmetic number, because the mean of its divisors is an integer number (117001227).

Almost surely, 2^668578420 is an apocalyptic number.

It is an amenable number.

668578420 is an abundant number, since it is smaller than the sum of its proper divisors (735436304).

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

668578420 is a wasteful number, since it uses less digits than its factorization.

668578420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33428930 (or 33428928 counting only the distinct ones).

The product of its (nonzero) digits is 645120, while the sum is 46.

The square root of 668578420 is about 25856.8834162201. The cubic root of 668578420 is about 874.4147029975.

The spelling of 668578420 in words is "six hundred sixty-eight million, five hundred seventy-eight thousand, four hundred twenty".