20975 has 6 divisors (see below), whose sum is σ = 26040. Its totient is φ = 16760.

The previous prime is 20963. The next prime is 20981. The reversal of 20975 is 57902.

20975 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 20975 - 2⁴ = 20959 is a prime.

20975 is strictly pandigital in base 6.

It is a self number, because there is not a number n which added to its sum of digits gives 20975.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 395 + ... + 444.

It is an arithmetic number, because the mean of its divisors is an integer number (4340).

2²⁰⁹⁷⁵ is an apocalyptic number.

20975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20975 is a deficient number, since it is larger than the sum of its proper divisors (5065).

20975 is an equidigital number, since it uses as much as digits as its factorization.

20975 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 849 (or 844 counting only the distinct ones).

The product of its (nonzero) digits is 630, while the sum is 23.

The square root of 20975 is about 144.8274835796. The cubic root of 20975 is about 27.5782893046.

The spelling of 20975 in words is "twenty thousand, nine hundred seventy-five".