21122121017 has 2 divisors, whose sum is σ = 21122121018. Its totient is φ = 21122121016.

The previous prime is 21122120993. The next prime is 21122121023. The reversal of 21122121017 is 71012122112.

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., 18551529616 + 2570591401 = 136204^2 + 50701^2 .

It is a cyclic number.

It is not a de Polignac number, because 21122121017 - 2⁶ = 21122120953 is a prime.

It is a super-2 number, since 2×21122121017² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21122121017.

It is not a weakly prime, because it can be changed into another prime (21122121037) 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, 10561060508 + 10561060509.

It is an arithmetic number, because the mean of its divisors is an integer number (10561060509).

Almost surely, 2^21122121017 is an apocalyptic number.

It is an amenable number.

21122121017 is a deficient number, since it is larger than the sum of its proper divisors (1).

21122121017 is an equidigital number, since it uses as much as digits as its factorization.

21122121017 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 21122121017 its reverse (71012122112), we get a palindrome (92134243129).

The spelling of 21122121017 in words is "twenty-one billion, one hundred twenty-two million, one hundred twenty-one thousand, seventeen".