20121221117 has 2 divisors, whose sum is σ = 20121221118. Its totient is φ = 20121221116.

The previous prime is 20121221041. The next prime is 20121221129. The reversal of 20121221117 is 71112212102.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18221220196 + 1900000921 = 134986^2 + 43589^2 .

It is a cyclic number.

It is not a de Polignac number, because 20121221117 - 2¹⁸ = 20120958973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20121221137) 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, 10060610558 + 10060610559.

It is an arithmetic number, because the mean of its divisors is an integer number (10060610559).

Almost surely, 2^20121221117 is an apocalyptic number.

It is an amenable number.

20121221117 is a deficient number, since it is larger than the sum of its proper divisors (1).

20121221117 is an equidigital number, since it uses as much as digits as its factorization.

20121221117 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 20121221117 its reverse (71112212102), we get a palindrome (91233433219).

The spelling of 20121221117 in words is "twenty billion, one hundred twenty-one million, two hundred twenty-one thousand, one hundred seventeen".