21819663836309 has 2 divisors, whose sum is σ = 21819663836310. Its totient is φ = 21819663836308.

The previous prime is 21819663836273. The next prime is 21819663836339. The reversal of 21819663836309 is 90363836691812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21819147183409 + 516652900 = 4671097^2 + 22730^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21819663836309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21819663836339) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10909831918154 + 10909831918155.

It is an arithmetic number, because the mean of its divisors is an integer number (10909831918155).

Almost surely, 2^{21819663836309} is an apocalyptic number.

It is an amenable number.

21819663836309 is a deficient number, since it is larger than the sum of its proper divisors (1).

21819663836309 is an equidigital number, since it uses as much as digits as its factorization.

21819663836309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 60466176, while the sum is 65.

The spelling of 21819663836309 in words is "twenty-one trillion, eight hundred nineteen billion, six hundred sixty-three million, eight hundred thirty-six thousand, three hundred nine".