21003133 has 4 divisors (see below), whose sum is σ = 21168640. Its totient is φ = 20837628.

The previous prime is 21003121. The next prime is 21003139. The reversal of 21003133 is 33130012.

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.

It is a cyclic number.

It is not a de Polignac number, because 21003133 - 2⁹ = 21002621 is a prime.

It is a super-2 number, since 2×21003133² = 882263191631378, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21003139) 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, 82563 + ... + 82816.

It is an arithmetic number, because the mean of its divisors is an integer number (5292160).

Almost surely, 2^21003133 is an apocalyptic number.

It is an amenable number.

21003133 is a deficient number, since it is larger than the sum of its proper divisors (165507).

21003133 is a wasteful number, since it uses less digits than its factorization.

21003133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165506.

The product of its (nonzero) digits is 54, while the sum is 13.

The square root of 21003133 is about 4582.9175205321. The cubic root of 21003133 is about 275.9061371296.

Adding to 21003133 its reverse (33130012), we get a palindrome (54133145).

The spelling of 21003133 in words is "twenty-one million, three thousand, one hundred thirty-three".