21200120171 has 2 divisors, whose sum is σ = 21200120172. Its totient is φ = 21200120170.

The previous prime is 21200120167. The next prime is 21200120203. The reversal of 21200120171 is 17102100212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21200120171 - 2² = 21200120167 is a prime.

It is not a weakly prime, because it can be changed into another prime (21200120971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600060085 + 10600060086.

It is an arithmetic number, because the mean of its divisors is an integer number (10600060086).

Almost surely, 2^21200120171 is an apocalyptic number.

21200120171 is a deficient number, since it is larger than the sum of its proper divisors (1).

21200120171 is an equidigital number, since it uses as much as digits as its factorization.

21200120171 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 56, while the sum is 17.

Adding to 21200120171 its reverse (17102100212), we get a palindrome (38302220383).

The spelling of 21200120171 in words is "twenty-one billion, two hundred million, one hundred twenty thousand, one hundred seventy-one".