21201212012243 has 2 divisors, whose sum is σ = 21201212012244. Its totient is φ = 21201212012242.

The previous prime is 21201212012209. The next prime is 21201212012263. The reversal of 21201212012243 is 34221021210212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21201212012243 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21201212012263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600606006121 + 10600606006122.

It is an arithmetic number, because the mean of its divisors is an integer number (10600606006122).

Almost surely, 2^{21201212012243} is an apocalyptic number.

21201212012243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201212012243 is an equidigital number, since it uses as much as digits as its factorization.

21201212012243 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 768, while the sum is 23.

Adding to 21201212012243 its reverse (34221021210212), we get a palindrome (55422233222455).

The spelling of 21201212012243 in words is "twenty-one trillion, two hundred one billion, two hundred twelve million, twelve thousand, two hundred forty-three".