20112111221 has 2 divisors, whose sum is σ = 20112111222. Its totient is φ = 20112111220.

The previous prime is 20112111209. The next prime is 20112111223. The reversal of 20112111221 is 12211121102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16702719121 + 3409392100 = 129239^2 + 58390^2 .

It is a cyclic number.

It is not a de Polignac number, because 20112111221 - 2⁶ = 20112111157 is a prime.

It is a super-2 number, since 2×20112111221² (a number of 21 digits) contains 22 as substring.

Together with 20112111223, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20112111196 and 20112111205.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20112111223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10056055610 + 10056055611.

It is an arithmetic number, because the mean of its divisors is an integer number (10056055611).

Almost surely, 2^20112111221 is an apocalyptic number.

It is an amenable number.

20112111221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20112111221 is an equidigital number, since it uses as much as digits as its factorization.

20112111221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 20112111221 its reverse (12211121102), we get a palindrome (32323232323).

The spelling of 20112111221 in words is "twenty billion, one hundred twelve million, one hundred eleven thousand, two hundred twenty-one".