668668140 has 576 divisors, whose sum is σ = 2717245440. Its totient is φ = 129392640.

The previous prime is 668668127. The next prime is 668668141. The reversal of 668668140 is 41866866.

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

It is not an unprimeable number, because it can be changed into a prime (668668141) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 12616354 + ... + 12616406.

It is an arithmetic number, because the mean of its divisors is an integer number (4717440).

Almost surely, 2^668668140 is an apocalyptic number.

668668140 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 668668140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1358622720).

668668140 is an abundant number, since it is smaller than the sum of its proper divisors (2048577300).

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

668668140 is a wasteful number, since it uses less digits than its factorization.

668668140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142 (or 137 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 45.

The square root of 668668140 is about 25858.6182925538. The cubic root of 668668140 is about 874.4538153269.

The spelling of 668668140 in words is "six hundred sixty-eight million, six hundred sixty-eight thousand, one hundred forty".