21063 has 16 divisors (see below), whose sum is σ = 34560. Its totient is φ = 11136.

The previous prime is 21061. The next prime is 21067. The reversal of 21063 is 36012.

It is not a de Polignac number, because 21063 - 2¹ = 21061 is a prime.

21063 is a modest number, since divided by 63 gives 21 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 328 + ... + 386.

It is an arithmetic number, because the mean of its divisors is an integer number (2160).

2²¹⁰⁶³ is an apocalyptic number.

21063 is a deficient number, since it is larger than the sum of its proper divisors (13497).

21063 is a wasteful number, since it uses less digits than its factorization.

21063 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86.

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 21063 is about 145.1309753292. The cubic root of 21063 is about 27.6168034622.

Adding to 21063 its reverse (36012), we get a palindrome (57075).

The spelling of 21063 in words is "twenty-one thousand, sixty-three".