20563 has 2 divisors, whose sum is σ = 20564. Its totient is φ = 20562.

The previous prime is 20551. The next prime is 20593. The reversal of 20563 is 36502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20563 - 2⁹ = 20051 is a prime.

20563 is a lucky number.

It is a nialpdrome in base 12.

It is not a weakly prime, because it can be changed into another prime (20533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10281 + 10282.

It is an arithmetic number, because the mean of its divisors is an integer number (10282).

2²⁰⁵⁶³ is an apocalyptic number.

20563 is a deficient number, since it is larger than the sum of its proper divisors (1).

20563 is an equidigital number, since it uses as much as digits as its factorization.

20563 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 180, while the sum is 16.

The square root of 20563 is about 143.3980474065. The cubic root of 20563 is about 27.3965257463.

The spelling of 20563 in words is "twenty thousand, five hundred sixty-three".