20973 has 4 divisors (see below), whose sum is σ = 27968. Its totient is φ = 13980.

The previous prime is 20963. The next prime is 20981. The reversal of 20973 is 37902.

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.

It is not a de Polignac number, because 20973 - 2⁸ = 20717 is a prime.

It is a d-powerful number, because it can be written as 2⁹ + 0 + 9³ + 7² + 3⁹ .

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20903) 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, 3493 + ... + 3498.

It is an arithmetic number, because the mean of its divisors is an integer number (6992).

2²⁰⁹⁷³ is an apocalyptic number.

It is an amenable number.

20973 is a deficient number, since it is larger than the sum of its proper divisors (6995).

20973 is an equidigital number, since it uses as much as digits as its factorization.

20973 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6994.

The product of its (nonzero) digits is 378, while the sum is 21.

The square root of 20973 is about 144.8205786482. The cubic root of 20973 is about 27.5774127320.

It can be divided in two parts, 209 and 73, that added together give a palindrome (282).

The spelling of 20973 in words is "twenty thousand, nine hundred seventy-three".