668393362728 has 768 divisors, whose sum is σ = 2328668160000. Its totient is φ = 173088534528.

The previous prime is 668393362709. The next prime is 668393362729. The reversal of 668393362728 is 827263393866.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (668393362729) 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, 5262939801 + ... + 5262939927.

It is an arithmetic number, because the mean of its divisors is an integer number (3032120000).

Almost surely, 2^668393362728 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 668393362728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1164334080000).

668393362728 is an abundant number, since it is smaller than the sum of its proper divisors (1660274797272).

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

668393362728 is a wasteful number, since it uses less digits than its factorization.

668393362728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 296 (or 249 counting only the distinct ones).

The product of its digits is 94058496, while the sum is 63.

The spelling of 668393362728 in words is "six hundred sixty-eight billion, three hundred ninety-three million, three hundred sixty-two thousand, seven hundred twenty-eight".