21008033 has 4 divisors (see below), whose sum is σ = 21017220. Its totient is φ = 20998848.

The previous prime is 21008027. The next prime is 21008041. The reversal of 21008033 is 33080012.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 13010449 + 7997584 = 3607^2 + 2828^2 .

It is a cyclic number.

It is not a de Polignac number, because 21008033 - 2¹² = 21003937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21008023) 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, 1853 + ... + 6741.

It is an arithmetic number, because the mean of its divisors is an integer number (5254305).

Almost surely, 2^21008033 is an apocalyptic number.

It is an amenable number.

21008033 is a deficient number, since it is larger than the sum of its proper divisors (9187).

21008033 is an equidigital number, since it uses as much as digits as its factorization.

21008033 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9186.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 21008033 is about 4583.4520833101. The cubic root of 21008033 is about 275.9275916264.

Adding to 21008033 its reverse (33080012), we get a palindrome (54088045).

The spelling of 21008033 in words is "twenty-one million, eight thousand, thirty-three".