21001112117 has 2 divisors, whose sum is σ = 21001112118. Its totient is φ = 21001112116.

The previous prime is 21001112071. The next prime is 21001112141. The reversal of 21001112117 is 71121110012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18923028721 + 2078083396 = 137561^2 + 45586^2 .

It is a cyclic number.

It is not a de Polignac number, because 21001112117 - 2¹² = 21001108021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21001112095 and 21001112104.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001192117) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500556058 + 10500556059.

It is an arithmetic number, because the mean of its divisors is an integer number (10500556059).

Almost surely, 2^21001112117 is an apocalyptic number.

It is an amenable number.

21001112117 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001112117 is an equidigital number, since it uses as much as digits as its factorization.

21001112117 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28, while the sum is 17.

Adding to 21001112117 its reverse (71121110012), we get a palindrome (92122222129).

The spelling of 21001112117 in words is "twenty-one billion, one million, one hundred twelve thousand, one hundred seventeen".