100565 has 4 divisors (see below), whose sum is σ = 120684. Its totient is φ = 80448.

The previous prime is 100559. The next prime is 100591. The reversal of 100565 is 565001.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 565001 = 251 ⋅2251.

It can be written as a sum of positive squares in 2 ways, for example, as 18769 + 81796 = 137^2 + 286^2 .

It is a cyclic number.

It is not a de Polignac number, because 100565 - 2⁴ = 100549 is a prime.

It is a super-2 number, since 2×100565² = 20226638450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10052 + ... + 10061.

It is an arithmetic number, because the mean of its divisors is an integer number (30171).

2¹⁰⁰⁵⁶⁵ is an apocalyptic number.

It is an amenable number.

100565 is a deficient number, since it is larger than the sum of its proper divisors (20119).

100565 is an equidigital number, since it uses as much as digits as its factorization.

100565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20118.

The product of its (nonzero) digits is 150, while the sum is 17.

The square root of 100565 is about 317.1198511604. The cubic root of 100565 is about 46.5031408061.

Adding to 100565 its reverse (565001), we get a palindrome (665566).

The spelling of 100565 in words is "one hundred thousand, five hundred sixty-five".