666900 has 144 divisors (see below), whose sum is σ = 2430400. Its totient is φ = 155520.

The previous prime is 666889. The next prime is 666901. The reversal of 666900 is 9666.

It is a super-2 number, since 2×666900² = 889511220000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666901) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 35091 + ... + 35109.

2⁶⁶⁶⁹⁰⁰ is an apocalyptic number.

666900 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 666900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1215200).

666900 is an abundant number, since it is smaller than the sum of its proper divisors (1763500).

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

666900 is a wasteful number, since it uses less digits than its factorization.

666900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55 (or 42 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 27.

The square root of 666900 is about 816.6394553290. The cubic root of 666900 is about 87.3682370569.

The spelling of 666900 in words is "six hundred sixty-six thousand, nine hundred".