21788416889 has 2 divisors, whose sum is σ = 21788416890. Its totient is φ = 21788416888.

The previous prime is 21788416823. The next prime is 21788416891. The reversal of 21788416889 is 98861488712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21702298489 + 86118400 = 147317^2 + 9280^2 .

It is a cyclic number.

It is not a de Polignac number, because 21788416889 - 2⁸ = 21788416633 is a prime.

It is a super-2 number, since 2×21788416889² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

Together with 21788416891, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21788416589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10894208444 + 10894208445.

It is an arithmetic number, because the mean of its divisors is an integer number (10894208445).

Almost surely, 2^21788416889 is an apocalyptic number.

It is an amenable number.

21788416889 is a deficient number, since it is larger than the sum of its proper divisors (1).

21788416889 is an equidigital number, since it uses as much as digits as its factorization.

21788416889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12386304, while the sum is 62.

The spelling of 21788416889 in words is "twenty-one billion, seven hundred eighty-eight million, four hundred sixteen thousand, eight hundred eighty-nine".