668481385336128 has 1120 divisors, whose sum is σ = 2506045835955200. Its totient is φ = 171452083912704.

The previous prime is 668481385336103. The next prime is 668481385336133. The reversal of 668481385336128 is 821633583184866.

668481385336128 is a `hidden beast` number, since 6 + 6 + 8 + 4 + 8 + 1 + 3 + 8 + 533 + 61 + 28 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 39604315593 + ... + 39604332471.

It is an arithmetic number, because the mean of its divisors is an integer number (2237540924960).

Almost surely, 2^{668481385336128} 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 668481385336128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1253022917977600).

668481385336128 is an abundant number, since it is smaller than the sum of its proper divisors (1837564450619072).

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

668481385336128 is a wasteful number, since it uses less digits than its factorization.

668481385336128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19229 (or 19210 counting only the distinct ones).

The product of its digits is 955514880, while the sum is 72.

It can be divided in two parts, 668481 and 385336128, that added together give a square (386004609 = 19647²).

The spelling of 668481385336128 in words is "six hundred sixty-eight trillion, four hundred eighty-one billion, three hundred eighty-five million, three hundred thirty-six thousand, one hundred twenty-eight".