21201111220171 has 2 divisors, whose sum is σ = 21201111220172. Its totient is φ = 21201111220170.

The previous prime is 21201111220129. The next prime is 21201111220181. The reversal of 21201111220171 is 17102211110212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21201111220171 - 2¹¹ = 21201111218123 is a prime.

It is not a weakly prime, because it can be changed into another prime (21201111220111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600555610085 + 10600555610086.

It is an arithmetic number, because the mean of its divisors is an integer number (10600555610086).

Almost surely, 2^{21201111220171} is an apocalyptic number.

21201111220171 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201111220171 is an equidigital number, since it uses as much as digits as its factorization.

21201111220171 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 112, while the sum is 22.

Adding to 21201111220171 its reverse (17102211110212), we get a palindrome (38303322330383).

The spelling of 21201111220171 in words is "twenty-one trillion, two hundred one billion, one hundred eleven million, two hundred twenty thousand, one hundred seventy-one".