668917800 has 144 divisors (see below), whose sum is σ = 2364804000. Its totient is φ = 168981120.

The previous prime is 668917793. The next prime is 668917807. The reversal of 668917800 is 8719866.

It is a happy number.

668917800 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (668917793) and next prime (668917807).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668917807) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 24421 + ... + 43979.

It is an arithmetic number, because the mean of its divisors is an integer number (16422250).

Almost surely, 2^668917800 is an apocalyptic number.

668917800 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 668917800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1182402000).

668917800 is an abundant number, since it is smaller than the sum of its proper divisors (1695886200).

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

668917800 is a wasteful number, since it uses less digits than its factorization.

668917800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19600 (or 19588 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The square root of 668917800 is about 25863.4452461384. The cubic root of 668917800 is about 874.5626331202.

It can be divided in two parts, 66891 and 7800, that added together give a triangular number (74691 = T₃₈₆).

The spelling of 668917800 in words is "six hundred sixty-eight million, nine hundred seventeen thousand, eight hundred".