21244133 has 4 divisors (see below), whose sum is σ = 21286380. Its totient is φ = 21201888.

The previous prime is 21244121. The next prime is 21244163. The reversal of 21244133 is 33144212.

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 19651489 + 1592644 = 4433^2 + 1262^2 .

It is a cyclic number.

It is not a de Polignac number, because 21244133 - 2²⁰ = 20195557 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21244163) 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, 20360 + ... + 21377.

It is an arithmetic number, because the mean of its divisors is an integer number (5321595).

Almost surely, 2^21244133 is an apocalyptic number.

It is an amenable number.

21244133 is a deficient number, since it is larger than the sum of its proper divisors (42247).

21244133 is an equidigital number, since it uses as much as digits as its factorization.

21244133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42246.

The product of its digits is 576, while the sum is 20.

The square root of 21244133 is about 4609.1358192182. The cubic root of 21244133 is about 276.9574193737.

Adding to 21244133 its reverse (33144212), we get a palindrome (54388345).

The spelling of 21244133 in words is "twenty-one million, two hundred forty-four thousand, one hundred thirty-three".