668993280 has 144 divisors (see below), whose sum is σ = 2163369600. Its totient is φ = 176164864.

The previous prime is 668993261. The next prime is 668993293. The reversal of 668993280 is 82399866.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 317671 + ... + 319769.

It is an arithmetic number, because the mean of its divisors is an integer number (15023400).

Almost surely, 2^668993280 is an apocalyptic number.

668993280 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 668993280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1081684800).

668993280 is an abundant number, since it is smaller than the sum of its proper divisors (1494376320).

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

668993280 is a wasteful number, since it uses less digits than its factorization.

668993280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2206 (or 2192 counting only the distinct ones).

The product of its (nonzero) digits is 1119744, while the sum is 51.

The square root of 668993280 is about 25864.9044073238. The cubic root of 668993280 is about 874.5955268005.

Adding to 668993280 its sum of digits (51), we get a triangular number (668993331 = T₃₆₅₇₈).

The spelling of 668993280 in words is "six hundred sixty-eight million, nine hundred ninety-three thousand, two hundred eighty".