668686740 has 48 divisors (see below), whose sum is σ = 1932725760. Its totient is φ = 172563840.

The previous prime is 668686729. The next prime is 668686747. The reversal of 668686740 is 47686866.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668686747) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 177895 + ... + 181614.

It is an arithmetic number, because the mean of its divisors is an integer number (40265120).

Almost surely, 2^668686740 is an apocalyptic number.

668686740 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

668686740 is an abundant number, since it is smaller than the sum of its proper divisors (1264039020).

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

668686740 is a wasteful number, since it uses less digits than its factorization.

668686740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 359552 (or 359550 counting only the distinct ones).

The product of its (nonzero) digits is 2322432, while the sum is 51.

The square root of 668686740 is about 25858.9779380392. The cubic root of 668686740 is about 874.4619233301.

The spelling of 668686740 in words is "six hundred sixty-eight million, six hundred eighty-six thousand, seven hundred forty".