20873 has 2 divisors, whose sum is σ = 20874. Its totient is φ = 20872.

The previous prime is 20857. The next prime is 20879. The reversal of 20873 is 37802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16384 + 4489 = 128^2 + 67^2 .

It is a cyclic number.

It is not a de Polignac number, because 20873 - 2⁴ = 20857 is a prime.

It is a plaindrome in base 7.

It is not a weakly prime, because it can be changed into another prime (20879) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10436 + 10437.

It is an arithmetic number, because the mean of its divisors is an integer number (10437).

2²⁰⁸⁷³ is an apocalyptic number.

It is an amenable number.

20873 is a deficient number, since it is larger than the sum of its proper divisors (1).

20873 is an equidigital number, since it uses as much as digits as its factorization.

20873 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 20873 is about 144.4749113168. The cubic root of 20873 is about 27.5335128620.

The spelling of 20873 in words is "twenty thousand, eight hundred seventy-three".