100666 has 4 divisors (see below), whose sum is σ = 151002. Its totient is φ = 50332.

The previous prime is 100649. The next prime is 100669. The reversal of 100666 is 666001.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 666001 = 7 ⋅95143.

It can be written as a sum of positive squares in only one way, i.e., 73441 + 27225 = 271^2 + 165^2 .

100666 is a modest number, since divided by 666 gives 100 as remainder.

It is not an unprimeable number, because it can be changed into a prime (100669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25165 + ... + 25168.

2¹⁰⁰⁶⁶⁶ is an apocalyptic number.

100666 is a deficient number, since it is larger than the sum of its proper divisors (50336).

100666 is an equidigital number, since it uses as much as digits as its factorization.

100666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50335.

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

The square root of 100666 is about 317.2790569830. The cubic root of 100666 is about 46.5187036948.

Adding to 100666 its reverse (666001), we get a palindrome (766667).

The spelling of 100666 in words is "one hundred thousand, six hundred sixty-six".