21733 has 4 divisors (see below), whose sum is σ = 22048. Its totient is φ = 21420.

The previous prime is 21727. The next prime is 21737. The reversal of 21733 is 33712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21733 - 2⁵ = 21701 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21737) 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, 3 + ... + 208.

It is an arithmetic number, because the mean of its divisors is an integer number (5512).

2²¹⁷³³ is an apocalyptic number.

It is an amenable number.

21733 is a deficient number, since it is larger than the sum of its proper divisors (315).

21733 is a wasteful number, since it uses less digits than its factorization.

21733 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 314.

The product of its digits is 126, while the sum is 16.

The square root of 21733 is about 147.4211653732. The cubic root of 21733 is about 27.9065763885.

The spelling of 21733 in words is "twenty-one thousand, seven hundred thirty-three".