668021760 has 528 divisors, whose sum is σ = 2810121600. Its totient is φ = 143327232.

The previous prime is 668021743. The next prime is 668021771. The reversal of 668021760 is 67120866.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6128586 + ... + 6128694.

It is an arithmetic number, because the mean of its divisors is an integer number (5322200).

Almost surely, 2^668021760 is an apocalyptic number.

668021760 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 668021760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1405060800).

668021760 is an abundant number, since it is smaller than the sum of its proper divisors (2142099840).

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

668021760 is a wasteful number, since it uses less digits than its factorization.

668021760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166 (or 145 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 668021760 is about 25846.1169230505. The cubic root of 668021760 is about 874.1719556864.

The spelling of 668021760 in words is "six hundred sixty-eight million, twenty-one thousand, seven hundred sixty".