21868616069 has 2 divisors, whose sum is σ = 21868616070. Its totient is φ = 21868616068.

The previous prime is 21868616017. The next prime is 21868616093. The reversal of 21868616069 is 96061686812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14414883844 + 7453732225 = 120062^2 + 86335^2 .

It is a cyclic number.

It is not a de Polignac number, because 21868616069 - 2³² = 17573648773 is a prime.

It is a super-2 number, since 2×21868616069² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21868616069.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21868616569) 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, 10934308034 + 10934308035.

It is an arithmetic number, because the mean of its divisors is an integer number (10934308035).

Almost surely, 2^21868616069 is an apocalyptic number.

It is an amenable number.

21868616069 is a deficient number, since it is larger than the sum of its proper divisors (1).

21868616069 is an equidigital number, since it uses as much as digits as its factorization.

21868616069 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1492992, while the sum is 53.

The spelling of 21868616069 in words is "twenty-one billion, eight hundred sixty-eight million, six hundred sixteen thousand, sixty-nine".