668821280 has 192 divisors, whose sum is σ = 1765048320. Its totient is φ = 238464000.

The previous prime is 668821277. The next prime is 668821313. The reversal of 668821280 is 82128866.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4429205 + ... + 4429355.

It is an arithmetic number, because the mean of its divisors is an integer number (9192960).

Almost surely, 2^668821280 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 668821280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (882524160).

668821280 is an abundant number, since it is smaller than the sum of its proper divisors (1096227040).

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

668821280 is a wasteful number, since it uses less digits than its factorization.

668821280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 263 (or 255 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 41.

The square root of 668821280 is about 25861.5792247883. The cubic root of 668821280 is about 874.5205667429.

The spelling of 668821280 in words is "six hundred sixty-eight million, eight hundred twenty-one thousand, two hundred eighty".