21002033 has 4 divisors (see below), whose sum is σ = 22617588. Its totient is φ = 19386480.

The previous prime is 21001991. The next prime is 21002039. The reversal of 21002033 is 33020012.

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

It can be written as a sum of positive squares in 2 ways, for example, as 14386849 + 6615184 = 3793^2 + 2572^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002033 - 2⁶ = 21001969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21002039) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 807758 + ... + 807783.

It is an arithmetic number, because the mean of its divisors is an integer number (5654397).

Almost surely, 2^21002033 is an apocalyptic number.

It is an amenable number.

21002033 is a deficient number, since it is larger than the sum of its proper divisors (1615555).

21002033 is a wasteful number, since it uses less digits than its factorization.

21002033 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1615554.

The product of its (nonzero) digits is 36, while the sum is 11.

The square root of 21002033 is about 4582.7975080730. The cubic root of 21002033 is about 275.9013203554.

Adding to 21002033 its reverse (33020012), we get a palindrome (54022045).

The spelling of 21002033 in words is "twenty-one million, two thousand, thirty-three".