668442378240 has 1920 divisors, whose sum is σ = 3033395850240. Its totient is φ = 137594142720.

The previous prime is 668442378223. The next prime is 668442378271. The reversal of 668442378240 is 42873244866.

668442378240 is a `hidden beast` number, since 66 + 84 + 423 + 7 + 82 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1920).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 16303472620 + ... + 16303472660.

It is an arithmetic number, because the mean of its divisors is an integer number (1579893672).

Almost surely, 2^668442378240 is an apocalyptic number.

668442378240 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 668442378240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1516697925120).

668442378240 is an abundant number, since it is smaller than the sum of its proper divisors (2364953472000).

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

668442378240 is an frugal number, since it uses more digits than its factorization.

668442378240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115 (or 71 counting only the distinct ones).

The product of its (nonzero) digits is 12386304, while the sum is 54.

The spelling of 668442378240 in words is "six hundred sixty-eight billion, four hundred forty-two million, three hundred seventy-eight thousand, two hundred forty".