21216212424133 has 4 divisors (see below), whose sum is σ = 21216962433420. Its totient is φ = 21215462414848.

The previous prime is 21216212424103. The next prime is 21216212424157. The reversal of 21216212424133 is 33142421261212.

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 8705999051649 + 12510213372484 = 2950593^2 + 3536978^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21216212424133 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21216212424103) 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, 374962210 + ... + 375018787.

It is an arithmetic number, because the mean of its divisors is an integer number (5304240608355).

Almost surely, 2^{21216212424133} is an apocalyptic number.

It is an amenable number.

21216212424133 is a deficient number, since it is larger than the sum of its proper divisors (750009287).

21216212424133 is an equidigital number, since it uses as much as digits as its factorization.

21216212424133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 750009286.

The product of its digits is 27648, while the sum is 34.

Adding to 21216212424133 its reverse (33142421261212), we get a palindrome (54358633685345).

The spelling of 21216212424133 in words is "twenty-one trillion, two hundred sixteen billion, two hundred twelve million, four hundred twenty-four thousand, one hundred thirty-three".