21111220121171 has 2 divisors, whose sum is σ = 21111220121172. Its totient is φ = 21111220121170.

The previous prime is 21111220121021. The next prime is 21111220121179. The reversal of 21111220121171 is 17112102211112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21111220121171 - 2¹⁰ = 21111220120147 is a prime.

It is a super-2 number, since 2×21111220121171² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21111220121179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555610060585 + 10555610060586.

It is an arithmetic number, because the mean of its divisors is an integer number (10555610060586).

Almost surely, 2^{21111220121171} is an apocalyptic number.

21111220121171 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111220121171 is an equidigital number, since it uses as much as digits as its factorization.

21111220121171 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 112, while the sum is 23.

Adding to 21111220121171 its reverse (17112102211112), we get a palindrome (38223322332283).

The spelling of 21111220121171 in words is "twenty-one trillion, one hundred eleven billion, two hundred twenty million, one hundred twenty-one thousand, one hundred seventy-one".