21212444243 has 2 divisors, whose sum is σ = 21212444244. Its totient is φ = 21212444242.

The previous prime is 21212444233. The next prime is 21212444261. The reversal of 21212444243 is 34244421212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21212444243 - 2⁶ = 21212444179 is a prime.

It is not a weakly prime, because it can be changed into another prime (21212444233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606222121 + 10606222122.

It is an arithmetic number, because the mean of its divisors is an integer number (10606222122).

Almost surely, 2^21212444243 is an apocalyptic number.

21212444243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212444243 is an equidigital number, since it uses as much as digits as its factorization.

21212444243 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12288, while the sum is 29.

Adding to 21212444243 its reverse (34244421212), we get a palindrome (55456865455).

The spelling of 21212444243 in words is "twenty-one billion, two hundred twelve million, four hundred forty-four thousand, two hundred forty-three".