20112221 has 2 divisors, whose sum is σ = 20112222. Its totient is φ = 20112220.

The previous prime is 20112217. The next prime is 20112223. The reversal of 20112221 is 12221102.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18705625 + 1406596 = 4325^2 + 1186^2 .

It is a cyclic number.

It is not a de Polignac number, because 20112221 - 2² = 20112217 is a prime.

Together with 20112223, 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 (20112223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10056110 + 10056111.

It is an arithmetic number, because the mean of its divisors is an integer number (10056111).

Almost surely, 2^20112221 is an apocalyptic number.

It is an amenable number.

20112221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20112221 is an equidigital number, since it uses as much as digits as its factorization.

20112221 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 11.

The square root of 20112221 is about 4484.6650934044. The cubic root of 20112221 is about 271.9485061474.

Adding to 20112221 its reverse (12221102), we get a palindrome (32333323).

The spelling of 20112221 in words is "twenty million, one hundred twelve thousand, two hundred twenty-one".