666100 has 18 divisors (see below), whose sum is σ = 1445654. Its totient is φ = 266400.

The previous prime is 666091. The next prime is 666109. The reversal of 666100 is 1666.

It is a happy number.

666100 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (666091) and next prime (666109).

It can be written as a sum of positive squares in 3 ways, for example, as 164836 + 501264 = 406^2 + 708^2 .

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666109) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3231 + ... + 3430.

2⁶⁶⁶¹⁰⁰ is an apocalyptic number.

It is an amenable number.

666100 is an abundant number, since it is smaller than the sum of its proper divisors (779554).

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

666100 is a wasteful number, since it uses less digits than its factorization.

666100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6675 (or 6668 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 666100 is about 816.1494961096. The cubic root of 666100 is about 87.3332880109. Note that the first 3 decimals are identical.

Adding to 666100 its reverse (1666), we get a palindrome (667766).

The spelling of 666100 in words is "six hundred sixty-six thousand, one hundred".