21112212811 has 2 divisors, whose sum is σ = 21112212812. Its totient is φ = 21112212810.

The previous prime is 21112212809. The next prime is 21112212833. The reversal of 21112212811 is 11821221112.

It is a happy number.

It is an a-pointer prime, because the next prime (21112212833) can be obtained adding 21112212811 to its sum of digits (22).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21112212811 - 2¹ = 21112212809 is a prime.

Together with 21112212809, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21112812811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10556106405 + 10556106406.

It is an arithmetic number, because the mean of its divisors is an integer number (10556106406).

Almost surely, 2^21112212811 is an apocalyptic number.

21112212811 is a deficient number, since it is larger than the sum of its proper divisors (1).

21112212811 is an equidigital number, since it uses as much as digits as its factorization.

21112212811 is an evil number, because the sum of its binary digits is even.

The product of its digits is 128, while the sum is 22.

Adding to 21112212811 its reverse (11821221112), we get a palindrome (32933433923).

The spelling of 21112212811 in words is "twenty-one billion, one hundred twelve million, two hundred twelve thousand, eight hundred eleven".