668131660 has 72 divisors (see below), whose sum is σ = 1636921440. Its totient is φ = 228404736.

The previous prime is 668131619. The next prime is 668131661. The reversal of 668131660 is 66131866.

It is a happy number.

668131660 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (668131661) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 429444 + ... + 430996.

It is an arithmetic number, because the mean of its divisors is an integer number (22735020).

Almost surely, 2^668131660 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 668131660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (818460720).

668131660 is an abundant number, since it is smaller than the sum of its proper divisors (968789780).

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

668131660 is a wasteful number, since it uses less digits than its factorization.

668131660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2015 (or 2006 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 37.

The square root of 668131660 is about 25848.2428803197. The cubic root of 668131660 is about 874.2198913654.

The spelling of 668131660 in words is "six hundred sixty-eight million, one hundred thirty-one thousand, six hundred sixty".