666490400 has 72 divisors (see below), whose sum is σ = 1635715620. Its totient is φ = 265180160.

The previous prime is 666490397. The next prime is 666490459. The reversal of 666490400 is 4094666.

666490400 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 6 ways, for example, as 627602704 + 38887696 = 25052^2 + 6236^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 155486 + ... + 159714.

Almost surely, 2^666490400 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 666490400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (817857810).

666490400 is an abundant number, since it is smaller than the sum of its proper divisors (969225220).

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

666490400 is a wasteful number, since it uses less digits than its factorization.

666490400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4446 (or 4433 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 35.

The square root of 666490400 is about 25816.4753597388. The cubic root of 666490400 is about 873.5034663915.

The spelling of 666490400 in words is "six hundred sixty-six million, four hundred ninety thousand, four hundred".