21868616017 has 2 divisors, whose sum is σ = 21868616018. Its totient is φ = 21868616016.

The previous prime is 21868615997. The next prime is 21868616069. The reversal of 21868616017 is 71061686812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19112786001 + 2755830016 = 138249^2 + 52496^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21868616017 is a prime.

It is not a weakly prime, because it can be changed into another prime (21868646017) 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, 10934308008 + 10934308009.

It is an arithmetic number, because the mean of its divisors is an integer number (10934308009).

Almost surely, 2^21868616017 is an apocalyptic number.

It is an amenable number.

21868616017 is a deficient number, since it is larger than the sum of its proper divisors (1).

21868616017 is an equidigital number, since it uses as much as digits as its factorization.

21868616017 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 193536, while the sum is 46.

It can be divided in two parts, 21868 and 616017, that added together give a triangular number (637885 = T₁₁₂₉).

The spelling of 21868616017 in words is "twenty-one billion, eight hundred sixty-eight million, six hundred sixteen thousand, seventeen".