668534400 has 288 divisors, whose sum is σ = 2417032800. Its totient is φ = 175933440.

The previous prime is 668534371. The next prime is 668534407. The reversal of 668534400 is 4435866.

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 (36).

It is not an unprimeable number, because it can be changed into a prime (668534407) 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, 4003117 + ... + 4003283.

It is an arithmetic number, because the mean of its divisors is an integer number (8392475).

Almost surely, 2^668534400 is an apocalyptic number.

668534400 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 668534400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1208516400).

668534400 is an abundant number, since it is smaller than the sum of its proper divisors (1748498400).

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

668534400 is a wasteful number, since it uses less digits than its factorization.

668534400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 336 (or 316 counting only the distinct ones).

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

The square root of 668534400 is about 25856.0321781978. The cubic root of 668534400 is about 874.3955117409.

It can be divided in two parts, 66853 and 4400, that added together give a triangular number (71253 = T₃₇₇).

The spelling of 668534400 in words is "six hundred sixty-eight million, five hundred thirty-four thousand, four hundred".