21011111201 has 2 divisors, whose sum is σ = 21011111202. Its totient is φ = 21011111200.

The previous prime is 21011111197. The next prime is 21011111203. The reversal of 21011111201 is 10211111012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19841539600 + 1169571601 = 140860^2 + 34199^2 .

It is a cyclic number.

It is not a de Polignac number, because 21011111201 - 2² = 21011111197 is a prime.

Together with 21011111203, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21011111203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505555600 + 10505555601.

It is an arithmetic number, because the mean of its divisors is an integer number (10505555601).

Almost surely, 2^21011111201 is an apocalyptic number.

It is an amenable number.

21011111201 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011111201 is an equidigital number, since it uses as much as digits as its factorization.

21011111201 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 21011111201 its reverse (10211111012), we get a palindrome (31222222213).

The spelling of 21011111201 in words is "twenty-one billion, eleven million, one hundred eleven thousand, two hundred one".