21111012222061 has 2 divisors, whose sum is σ = 21111012222062. Its totient is φ = 21111012222060.

The previous prime is 21111012221993. The next prime is 21111012222077. The reversal of 21111012222061 is 16022221011112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18836737097161 + 2274275124900 = 4340131^2 + 1508070^2 .

It is a cyclic number.

It is not a de Polignac number, because 21111012222061 - 2⁹ = 21111012221549 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21111012222161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555506111030 + 10555506111031.

It is an arithmetic number, because the mean of its divisors is an integer number (10555506111031).

Almost surely, 2^{21111012222061} is an apocalyptic number.

It is an amenable number.

21111012222061 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111012222061 is an equidigital number, since it uses as much as digits as its factorization.

21111012222061 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 22.

Adding to 21111012222061 its reverse (16022221011112), we get a palindrome (37133233233173).

The spelling of 21111012222061 in words is "twenty-one trillion, one hundred eleven billion, twelve million, two hundred twenty-two thousand, sixty-one".