21056276317 has 2 divisors, whose sum is σ = 21056276318. Its totient is φ = 21056276316.

The previous prime is 21056276299. The next prime is 21056276333. The reversal of 21056276317 is 71367265012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17039125156 + 4017151161 = 130534^2 + 63381^2 .

It is a cyclic number.

It is not a de Polignac number, because 21056276317 - 2¹¹ = 21056274269 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21056276317.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21056277317) 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, 10528138158 + 10528138159.

It is an arithmetic number, because the mean of its divisors is an integer number (10528138159).

Almost surely, 2^21056276317 is an apocalyptic number.

It is an amenable number.

21056276317 is a deficient number, since it is larger than the sum of its proper divisors (1).

21056276317 is an equidigital number, since it uses as much as digits as its factorization.

21056276317 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 105840, while the sum is 40.

The spelling of 21056276317 in words is "twenty-one billion, fifty-six million, two hundred seventy-six thousand, three hundred seventeen".