100661 has 4 divisors (see below), whose sum is σ = 109824. Its totient is φ = 91500.

The previous prime is 100649. The next prime is 100669. The reversal of 100661 is 166001.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 166001 = 11 ⋅15091.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-100661 is a prime.

It is a congruent number.

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 in 3 ways as a sum of consecutive naturals, for example, 4565 + ... + 4586.

It is an arithmetic number, because the mean of its divisors is an integer number (27456).

2¹⁰⁰⁶⁶¹ is an apocalyptic number.

100661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

100661 is a deficient number, since it is larger than the sum of its proper divisors (9163).

100661 is an equidigital number, since it uses as much as digits as its factorization.

100661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9162.

The product of its (nonzero) digits is 36, while the sum is 14.

The square root of 100661 is about 317.2711773862. The cubic root of 100661 is about 46.5179334998.

Adding to 100661 its reverse (166001), we get a palindrome (266662).

The spelling of 100661 in words is "one hundred thousand, six hundred sixty-one".