666644000 has 192 divisors, whose sum is σ = 1816214400. Its totient is φ = 238464000.

The previous prime is 666643993. The next prime is 666644003. The reversal of 666644000 is 446666.

It is a happy number.

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a nialpdrome in base 10.

It is a zygodrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (666644003) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4795931 + ... + 4796069.

It is an arithmetic number, because the mean of its divisors is an integer number (9459450).

Almost surely, 2^666644000 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666644000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (908107200).

666644000 is an abundant number, since it is smaller than the sum of its proper divisors (1149570400).

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

666644000 is a wasteful number, since it uses less digits than its factorization.

666644000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 284 (or 266 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 32.

The square root of 666644000 is about 25819.4500328725. The cubic root of 666644000 is about 873.5705640455.

The spelling of 666644000 in words is "six hundred sixty-six million, six hundred forty-four thousand".