21933 has 6 divisors (see below), whose sum is σ = 31694. Its totient is φ = 14616.

The previous prime is 21929. The next prime is 21937. The reversal of 21933 is 33912.

It is an interprime number because it is at equal distance from previous prime (21929) and next prime (21937).

It can be written as a sum of positive squares in only one way, i.e., 21609 + 324 = 147^2 + 18^2 .

It is not a de Polignac number, because 21933 - 2² = 21929 is a prime.

It is a Duffinian number.

It is a Curzon number.

21933 is a lucky number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21937) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1210 + ... + 1227.

2²¹⁹³³ is an apocalyptic number.

It is an amenable number.

21933 is a deficient number, since it is larger than the sum of its proper divisors (9761).

21933 is a wasteful number, since it uses less digits than its factorization.

21933 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2443 (or 2440 counting only the distinct ones).

The product of its digits is 162, while the sum is 18.

The square root of 21933 is about 148.0979405664. The cubic root of 21933 is about 27.9919194369.

It can be divided in two parts, 219 and 33, that multiplied together give a palindrome (7227).

The spelling of 21933 in words is "twenty-one thousand, nine hundred thirty-three".