21100421171 has 2 divisors, whose sum is σ = 21100421172. Its totient is φ = 21100421170.

The previous prime is 21100421093. The next prime is 21100421197. The reversal of 21100421171 is 17112400112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21100421171 - 2¹⁸ = 21100159027 is a prime.

It is a super-2 number, since 2×21100421171² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21100420171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550210585 + 10550210586.

It is an arithmetic number, because the mean of its divisors is an integer number (10550210586).

Almost surely, 2^21100421171 is an apocalyptic number.

21100421171 is a deficient number, since it is larger than the sum of its proper divisors (1).

21100421171 is an equidigital number, since it uses as much as digits as its factorization.

21100421171 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 20.

Adding to 21100421171 its reverse (17112400112), we get a palindrome (38212821283).

The spelling of 21100421171 in words is "twenty-one billion, one hundred million, four hundred twenty-one thousand, one hundred seventy-one".