21998763282809 has 2 divisors, whose sum is σ = 21998763282810. Its totient is φ = 21998763282808.

The previous prime is 21998763282799. The next prime is 21998763282887. The reversal of 21998763282809 is 90828236789912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11003835743209 + 10994927539600 = 3317203^2 + 3315860^2 .

It is a cyclic number.

It is not a de Polignac number, because 21998763282809 - 2¹⁶ = 21998763217273 is a prime.

It is not a weakly prime, because it can be changed into another prime (21998763282109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10999381641404 + 10999381641405.

It is an arithmetic number, because the mean of its divisors is an integer number (10999381641405).

Almost surely, 2^{21998763282809} is an apocalyptic number.

It is an amenable number.

21998763282809 is a deficient number, since it is larger than the sum of its proper divisors (1).

21998763282809 is an equidigital number, since it uses as much as digits as its factorization.

21998763282809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 376233984, while the sum is 74.

The spelling of 21998763282809 in words is "twenty-one trillion, nine hundred ninety-eight billion, seven hundred sixty-three million, two hundred eighty-two thousand, eight hundred nine".