21965366641 has 2 divisors, whose sum is σ = 21965366642. Its totient is φ = 21965366640.

The previous prime is 21965366581. The next prime is 21965366747. The reversal of 21965366641 is 14666356912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21412176241 + 553190400 = 146329^2 + 23520^2 .

It is a cyclic number.

It is not a de Polignac number, because 21965366641 - 2¹¹ = 21965364593 is a prime.

It is not a weakly prime, because it can be changed into another prime (21965306641) 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, 10982683320 + 10982683321.

It is an arithmetic number, because the mean of its divisors is an integer number (10982683321).

Almost surely, 2^21965366641 is an apocalyptic number.

It is an amenable number.

21965366641 is a deficient number, since it is larger than the sum of its proper divisors (1).

21965366641 is an equidigital number, since it uses as much as digits as its factorization.

21965366641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1399680, while the sum is 49.

The spelling of 21965366641 in words is "twenty-one billion, nine hundred sixty-five million, three hundred sixty-six thousand, six hundred forty-one".