21717776459 has 2 divisors, whose sum is σ = 21717776460. Its totient is φ = 21717776458.

The previous prime is 21717776449. The next prime is 21717776527. The reversal of 21717776459 is 95467771712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21717776459 - 2⁸ = 21717776203 is a prime.

It is not a weakly prime, because it can be changed into another prime (21717776429) 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, 10858888229 + 10858888230.

It is an arithmetic number, because the mean of its divisors is an integer number (10858888230).

Almost surely, 2^21717776459 is an apocalyptic number.

21717776459 is a deficient number, since it is larger than the sum of its proper divisors (1).

21717776459 is an equidigital number, since it uses as much as digits as its factorization.

21717776459 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5186160, while the sum is 56.

The spelling of 21717776459 in words is "twenty-one billion, seven hundred seventeen million, seven hundred seventy-six thousand, four hundred fifty-nine".