668725920 has 288 divisors, whose sum is σ = 2427594624. Its totient is φ = 167270400.

The previous prime is 668725909. The next prime is 668725931. The reversal of 668725920 is 29527866.

It is an interprime number because it is at equal distance from previous prime (668725909) and next prime (668725931).

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2020155 + ... + 2020485.

It is an arithmetic number, because the mean of its divisors is an integer number (8429148).

Almost surely, 2^668725920 is an apocalyptic number.

668725920 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 668725920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1213797312).

668725920 is an abundant number, since it is smaller than the sum of its proper divisors (1758868704).

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

668725920 is a wasteful number, since it uses less digits than its factorization.

668725920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 436 (or 425 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The square root of 668725920 is about 25859.7354974872. The cubic root of 668725920 is about 874.4790019545.

The spelling of 668725920 in words is "six hundred sixty-eight million, seven hundred twenty-five thousand, nine hundred twenty".