21002100221171 has 2 divisors, whose sum is σ = 21002100221172. Its totient is φ = 21002100221170.

The previous prime is 21002100221159. The next prime is 21002100221233. The reversal of 21002100221171 is 17112200120012.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21002100221171 is a prime.

It is a super-2 number, since 2×21002100221171² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21002100421171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501050110585 + 10501050110586.

It is an arithmetic number, because the mean of its divisors is an integer number (10501050110586).

Almost surely, 2^{21002100221171} is an apocalyptic number.

21002100221171 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002100221171 is an equidigital number, since it uses as much as digits as its factorization.

21002100221171 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 20.

Adding to 21002100221171 its reverse (17112200120012), we get a palindrome (38114300341183).

The spelling of 21002100221171 in words is "twenty-one trillion, two billion, one hundred million, two hundred twenty-one thousand, one hundred seventy-one".