21012120221171 has 2 divisors, whose sum is σ = 21012120221172. Its totient is φ = 21012120221170.

The previous prime is 21012120221137. The next prime is 21012120221293. The reversal of 21012120221171 is 17112202121012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21012120221171 - 2³⁸ = 20737242314227 is a prime.

It is a super-2 number, since 2×21012120221171² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21012320221171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506060110585 + 10506060110586.

It is an arithmetic number, because the mean of its divisors is an integer number (10506060110586).

Almost surely, 2^{21012120221171} is an apocalyptic number.

21012120221171 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012120221171 is an equidigital number, since it uses as much as digits as its factorization.

21012120221171 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 224, while the sum is 23.

Adding to 21012120221171 its reverse (17112202121012), we get a palindrome (38124322342183).

The spelling of 21012120221171 in words is "twenty-one trillion, twelve billion, one hundred twenty million, two hundred twenty-one thousand, one hundred seventy-one".