668243520 has 560 divisors, whose sum is σ = 2832445440. Its totient is φ = 146313216.

The previous prime is 668243507. The next prime is 668243539. The reversal of 668243520 is 25342866.

It is a tau number, because it is divible by the number of its divisors (560).

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 5261697 + ... + 5261823.

Almost surely, 2^668243520 is an apocalyptic number.

668243520 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 668243520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1416222720).

668243520 is an abundant number, since it is smaller than the sum of its proper divisors (2164201920).

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

668243520 is a wasteful number, since it uses less digits than its factorization.

668243520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192 (or 173 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 36.

The square root of 668243520 is about 25850.4065732050. The cubic root of 668243520 is about 874.2686765505.

The spelling of 668243520 in words is "six hundred sixty-eight million, two hundred forty-three thousand, five hundred twenty".