21111211221101 has 2 divisors, whose sum is σ = 21111211221102. Its totient is φ = 21111211221100.

The previous prime is 21111211221041. The next prime is 21111211221137. The reversal of 21111211221101 is 10112211211112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18612364782025 + 2498846439076 = 4314205^2 + 1580774^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21111211221101 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21111211221101.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21111211221301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555605610550 + 10555605610551.

It is an arithmetic number, because the mean of its divisors is an integer number (10555605610551).

Almost surely, 2^{21111211221101} is an apocalyptic number.

It is an amenable number.

21111211221101 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111211221101 is an equidigital number, since it uses as much as digits as its factorization.

21111211221101 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 17.

Adding to 21111211221101 its reverse (10112211211112), we get a palindrome (31223422432213).

The spelling of 21111211221101 in words is "twenty-one trillion, one hundred eleven billion, two hundred eleven million, two hundred twenty-one thousand, one hundred one".