20553 has 16 divisors (see below), whose sum is σ = 32256. Its totient is φ = 11520.

The previous prime is 20551. The next prime is 20563. The reversal of 20553 is 35502.

It is not a de Polignac number, because 20553 - 2¹ = 20551 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 648 + ... + 678.

It is an arithmetic number, because the mean of its divisors is an integer number (2016).

2²⁰⁵⁵³ is an apocalyptic number.

It is an amenable number.

20553 is a deficient number, since it is larger than the sum of its proper divisors (11703).

20553 is a wasteful number, since it uses less digits than its factorization.

20553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64.

The product of its (nonzero) digits is 150, while the sum is 15.

The square root of 20553 is about 143.3631751881. The cubic root of 20553 is about 27.3920839547.

The spelling of 20553 in words is "twenty thousand, five hundred fifty-three".