668606400 has 840 divisors, whose sum is σ = 3109789056. Its totient is φ = 136857600.

The previous prime is 668606381. The next prime is 668606401. The reversal of 668606400 is 4606866.

668606400 is a `hidden beast` number, since 6 + 6 + 8 + 6 + 0 + 640 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (840).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668606401) by changing a digit.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 9979167 + ... + 9979233.

Almost surely, 2^668606400 is an apocalyptic number.

668606400 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 668606400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1554894528).

668606400 is an abundant number, since it is smaller than the sum of its proper divisors (2441182656).

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

668606400 is a wasteful number, since it uses less digits than its factorization.

668606400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119 (or 95 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The square root of 668606400 is about 25857.4244657120. The cubic root of 668606400 is about 874.4269009095.

The spelling of 668606400 in words is "six hundred sixty-eight million, six hundred six thousand, four hundred".