21211012243 has 2 divisors, whose sum is σ = 21211012244. Its totient is φ = 21211012242.

The previous prime is 21211012189. The next prime is 21211012289. The reversal of 21211012243 is 34221011212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21211012243 - 2¹³ = 21211004051 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21211012243.

It is not a weakly prime, because it can be changed into another prime (21211010243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605506121 + 10605506122.

It is an arithmetic number, because the mean of its divisors is an integer number (10605506122).

Almost surely, 2^21211012243 is an apocalyptic number.

21211012243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21211012243 is an equidigital number, since it uses as much as digits as its factorization.

21211012243 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 21211012243 its reverse (34221011212), we get a palindrome (55432023455).

The spelling of 21211012243 in words is "twenty-one billion, two hundred eleven million, twelve thousand, two hundred forty-three".