21220012243 has 2 divisors, whose sum is σ = 21220012244. Its totient is φ = 21220012242.

The previous prime is 21220012241. The next prime is 21220012271. The reversal of 21220012243 is 34221002212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21220012243 - 2¹ = 21220012241 is a prime.

It is a super-4 number, since 4×21220012243⁴ (a number of 42 digits) contains 4444 as substring.

Together with 21220012241, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21220012243.

It is not a weakly prime, because it can be changed into another prime (21220012241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610006121 + 10610006122.

It is an arithmetic number, because the mean of its divisors is an integer number (10610006122).

Almost surely, 2^21220012243 is an apocalyptic number.

21220012243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220012243 is an equidigital number, since it uses as much as digits as its factorization.

21220012243 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 19.

Adding to 21220012243 its reverse (34221002212), we get a palindrome (55441014455).

The spelling of 21220012243 in words is "twenty-one billion, two hundred twenty million, twelve thousand, two hundred forty-three".