205969 has 4 divisors (see below), whose sum is σ = 209520. Its totient is φ = 202420.

The previous prime is 205967. The next prime is 205981. The reversal of 205969 is 969502.

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: 969502 = 2 ⋅484751.

It is a cyclic number.

It is not a de Polignac number, because 205969 - 2¹ = 205967 is a prime.

It is a super-2 number, since 2×205969² = 84846457922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a nialpdrome in base 8.

It is a self number, because there is not a number n which added to its sum of digits gives 205969.

It is not an unprimeable number, because it can be changed into a prime (205963) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1687 + ... + 1804.

It is an arithmetic number, because the mean of its divisors is an integer number (52380).

2²⁰⁵⁹⁶⁹ is an apocalyptic number.

It is an amenable number.

205969 is a deficient number, since it is larger than the sum of its proper divisors (3551).

205969 is an equidigital number, since it uses as much as digits as its factorization.

205969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3550.

The product of its (nonzero) digits is 4860, while the sum is 31.

The square root of 205969 is about 453.8380768512. The cubic root of 205969 is about 59.0564431608.

The spelling of 205969 in words is "two hundred five thousand, nine hundred sixty-nine".