21033 has 16 divisors (see below), whose sum is σ = 33600. Its totient is φ = 12960.

The previous prime is 21031. The next prime is 21059. The reversal of 21033 is 33012.

It is a happy number.

It is not a de Polignac number, because 21033 - 2¹ = 21031 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21031) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 493 + ... + 533.

It is an arithmetic number, because the mean of its divisors is an integer number (2100).

2²¹⁰³³ is an apocalyptic number.

It is an amenable number.

21033 is a deficient number, since it is larger than the sum of its proper divisors (12567).

21033 is a wasteful number, since it uses less digits than its factorization.

21033 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69 (or 63 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 9.

The square root of 21033 is about 145.0275835833. The cubic root of 21033 is about 27.6036857082.

Adding to 21033 its reverse (33012), we get a palindrome (54045).

It can be divided in two parts, 210 and 33, that added together give a 5-th power (243 = 3⁵).

The spelling of 21033 in words is "twenty-one thousand, thirty-three".