21204210133 has 2 divisors, whose sum is σ = 21204210134. Its totient is φ = 21204210132.

The previous prime is 21204210127. The next prime is 21204210151. The reversal of 21204210133 is 33101240212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18298784529 + 2905425604 = 135273^2 + 53902^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21204210133 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21204210133.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21204213133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10602105066 + 10602105067.

It is an arithmetic number, because the mean of its divisors is an integer number (10602105067).

Almost surely, 2^21204210133 is an apocalyptic number.

It is an amenable number.

21204210133 is a deficient number, since it is larger than the sum of its proper divisors (1).

21204210133 is an equidigital number, since it uses as much as digits as its factorization.

21204210133 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 21204210133 its reverse (33101240212), we get a palindrome (54305450345).

It can be divided in two parts, 2120 and 4210133, that added together give a triangular number (4212253 = T₂₉₀₂).

The spelling of 21204210133 in words is "twenty-one billion, two hundred four million, two hundred ten thousand, one hundred thirty-three".