21001200122171 has 2 divisors, whose sum is σ = 21001200122172. Its totient is φ = 21001200122170.

The previous prime is 21001200122117. The next prime is 21001200122257. The reversal of 21001200122171 is 17122100210012.

It is a happy number.

Together with previous prime (21001200122117) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21001200122171 - 2³⁸ = 20726322215227 is a prime.

It is not a weakly prime, because it can be changed into another prime (21001200122101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500600061085 + 10500600061086.

It is an arithmetic number, because the mean of its divisors is an integer number (10500600061086).

Almost surely, 2^{21001200122171} is an apocalyptic number.

21001200122171 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001200122171 is an equidigital number, since it uses as much as digits as its factorization.

21001200122171 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 21001200122171 its reverse (17122100210012), we get a palindrome (38123300332183).

The spelling of 21001200122171 in words is "twenty-one trillion, one billion, two hundred million, one hundred twenty-two thousand, one hundred seventy-one".