20121221220017 has 2 divisors, whose sum is σ = 20121221220018. Its totient is φ = 20121221220016.

The previous prime is 20121221219999. The next prime is 20121221220103. The reversal of 20121221220017 is 71002212212102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19230294775696 + 890926444321 = 4385236^2 + 943889^2 .

It is a cyclic number.

It is not a de Polignac number, because 20121221220017 - 2¹⁶ = 20121221154481 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20121221219974 and 20121221220001.

It is not a weakly prime, because it can be changed into another prime (20121221222017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10060610610008 + 10060610610009.

It is an arithmetic number, because the mean of its divisors is an integer number (10060610610009).

Almost surely, 2^{20121221220017} is an apocalyptic number.

It is an amenable number.

20121221220017 is a deficient number, since it is larger than the sum of its proper divisors (1).

20121221220017 is an equidigital number, since it uses as much as digits as its factorization.

20121221220017 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 448, while the sum is 23.

Adding to 20121221220017 its reverse (71002212212102), we get a palindrome (91123433432119).

The spelling of 20121221220017 in words is "twenty trillion, one hundred twenty-one billion, two hundred twenty-one million, two hundred twenty thousand, seventeen".