20969 has 4 divisors (see below), whose sum is σ = 22596. Its totient is φ = 19344.

The previous prime is 20963. The next prime is 20981. The reversal of 20969 is 96902.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7744 + 13225 = 88^2 + 115^2 .

It is a de Polignac number, because none of the positive numbers 2^k-20969 is a prime.

It is a super-2 number, since 2×20969² = 879397922, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (20963) 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, 794 + ... + 819.

It is an arithmetic number, because the mean of its divisors is an integer number (5649).

2²⁰⁹⁶⁹ is an apocalyptic number.

It is an amenable number.

20969 is a deficient number, since it is larger than the sum of its proper divisors (1627).

20969 is a wasteful number, since it uses less digits than its factorization.

20969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1626.

The product of its (nonzero) digits is 972, while the sum is 26.

The square root of 20969 is about 144.8067677976. The cubic root of 20969 is about 27.5756594196.

It can be divided in two parts, 20 and 969, that added together give a palindrome (989).

The spelling of 20969 in words is "twenty thousand, nine hundred sixty-nine".