21363 has 4 divisors (see below), whose sum is σ = 28488. Its totient is φ = 14240.

The previous prime is 21347. The next prime is 21377. The reversal of 21363 is 36312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21363 - 2⁴ = 21347 is a prime.

It is a D-number.

It is a plaindrome in base 14.

It is a nialpdrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (21313) 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, 3558 + ... + 3563.

It is an arithmetic number, because the mean of its divisors is an integer number (7122).

2²¹³⁶³ is an apocalyptic number.

21363 is a deficient number, since it is larger than the sum of its proper divisors (7125).

21363 is an equidigital number, since it uses as much as digits as its factorization.

21363 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7124.

The product of its digits is 108, while the sum is 15.

The square root of 21363 is about 146.1608702766. The cubic root of 21363 is about 27.7473010929.

Adding to 21363 its reverse (36312), we get a palindrome (57675).

It can be divided in two parts, 213 and 63, that added together give a triangular number (276 = T₂₃).

The spelling of 21363 in words is "twenty-one thousand, three hundred sixty-three".