21421121171 has 2 divisors, whose sum is σ = 21421121172. Its totient is φ = 21421121170.

The previous prime is 21421121149. The next prime is 21421121203. The reversal of 21421121171 is 17112112412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21421121171 - 2³⁰ = 20347379347 is a prime.

It is a super-2 number, since 2×21421121171² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21421121131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10710560585 + 10710560586.

It is an arithmetic number, because the mean of its divisors is an integer number (10710560586).

Almost surely, 2^21421121171 is an apocalyptic number.

21421121171 is a deficient number, since it is larger than the sum of its proper divisors (1).

21421121171 is an equidigital number, since it uses as much as digits as its factorization.

21421121171 is an evil number, because the sum of its binary digits is even.

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

Adding to 21421121171 its reverse (17112112412), we get a palindrome (38533233583).

The spelling of 21421121171 in words is "twenty-one billion, four hundred twenty-one million, one hundred twenty-one thousand, one hundred seventy-one".