21778986269 has 2 divisors, whose sum is σ = 21778986270. Its totient is φ = 21778986268.

The previous prime is 21778986259. The next prime is 21778986293. The reversal of 21778986269 is 96268987712.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19213563769 + 2565422500 = 138613^2 + 50650^2 .

It is a cyclic number.

It is not a de Polignac number, because 21778986269 - 2⁴ = 21778986253 is a prime.

It is a super-2 number, since 2×21778986269² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21778986259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10889493134 + 10889493135.

It is an arithmetic number, because the mean of its divisors is an integer number (10889493135).

Almost surely, 2^21778986269 is an apocalyptic number.

It is an amenable number.

21778986269 is a deficient number, since it is larger than the sum of its proper divisors (1).

21778986269 is an equidigital number, since it uses as much as digits as its factorization.

21778986269 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36578304, while the sum is 65.

The spelling of 21778986269 in words is "twenty-one billion, seven hundred seventy-eight million, nine hundred eighty-six thousand, two hundred sixty-nine".