20442021217 has 2 divisors, whose sum is σ = 20442021218. Its totient is φ = 20442021216.

The previous prime is 20442021191. The next prime is 20442021227. The reversal of 20442021217 is 71212024402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20391554401 + 50466816 = 142799^2 + 7104^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20442021217 is a prime.

It is a super-2 number, since 2×20442021217² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20442021191 and 20442021200.

It is not a weakly prime, because it can be changed into another prime (20442021227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10221010608 + 10221010609.

It is an arithmetic number, because the mean of its divisors is an integer number (10221010609).

Almost surely, 2^20442021217 is an apocalyptic number.

It is an amenable number.

20442021217 is a deficient number, since it is larger than the sum of its proper divisors (1).

20442021217 is an equidigital number, since it uses as much as digits as its factorization.

20442021217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1792, while the sum is 25.

Adding to 20442021217 its reverse (71212024402), we get a palindrome (91654045619).

The spelling of 20442021217 in words is "twenty billion, four hundred forty-two million, twenty-one thousand, two hundred seventeen".