21220111219511 has 2 divisors, whose sum is σ = 21220111219512. Its totient is φ = 21220111219510.

The previous prime is 21220111219477. The next prime is 21220111219513. The reversal of 21220111219511 is 11591211102212.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21220111219511 is a prime.

It is a Sophie Germain prime.

Together with 21220111219513, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21220111219513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610055609755 + 10610055609756.

It is an arithmetic number, because the mean of its divisors is an integer number (10610055609756).

Almost surely, 2^{21220111219511} is an apocalyptic number.

21220111219511 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220111219511 is an equidigital number, since it uses as much as digits as its factorization.

21220111219511 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 720, while the sum is 29.

The spelling of 21220111219511 in words is "twenty-one trillion, two hundred twenty billion, one hundred eleven million, two hundred nineteen thousand, five hundred eleven".