20955 has 16 divisors (see below), whose sum is σ = 36864. Its totient is φ = 10080.

The previous prime is 20947. The next prime is 20959. The reversal of 20955 is 55902.

It is not a de Polignac number, because 20955 - 2³ = 20947 is a prime.

It is a super-2 number, since 2×20955² = 878224050, which contains 22 as substring.

It is a nialpdrome in base 15.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 20955.

It is not an unprimeable number, because it can be changed into a prime (20959) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 102 + ... + 228.

It is an arithmetic number, because the mean of its divisors is an integer number (2304).

2²⁰⁹⁵⁵ is an apocalyptic number.

20955 is a deficient number, since it is larger than the sum of its proper divisors (15909).

20955 is a wasteful number, since it uses less digits than its factorization.

20955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146.

The product of its (nonzero) digits is 450, while the sum is 21.

The square root of 20955 is about 144.7584194443. The cubic root of 20955 is about 27.5695210696.

The spelling of 20955 in words is "twenty thousand, nine hundred fifty-five".