21968041549 has 2 divisors, whose sum is σ = 21968041550. Its totient is φ = 21968041548.

The previous prime is 21968041523. The next prime is 21968041637. The reversal of 21968041549 is 94514086912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16000479049 + 5967562500 = 126493^2 + 77250^2 .

It is a cyclic number.

It is not a de Polignac number, because 21968041549 - 2²¹ = 21965944397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21968041649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10984020774 + 10984020775.

It is an arithmetic number, because the mean of its divisors is an integer number (10984020775).

Almost surely, 2^21968041549 is an apocalyptic number.

It is an amenable number.

21968041549 is a deficient number, since it is larger than the sum of its proper divisors (1).

21968041549 is an equidigital number, since it uses as much as digits as its factorization.

21968041549 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 622080, while the sum is 49.

The spelling of 21968041549 in words is "twenty-one billion, nine hundred sixty-eight million, forty-one thousand, five hundred forty-nine".