21864227813 has 2 divisors, whose sum is σ = 21864227814. Its totient is φ = 21864227812.

The previous prime is 21864227771. The next prime is 21864227843. The reversal of 21864227813 is 31872246812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21602532484 + 261695329 = 146978^2 + 16177^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21864227813 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21864227843) 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, 10932113906 + 10932113907.

It is an arithmetic number, because the mean of its divisors is an integer number (10932113907).

Almost surely, 2^21864227813 is an apocalyptic number.

It is an amenable number.

21864227813 is a deficient number, since it is larger than the sum of its proper divisors (1).

21864227813 is an equidigital number, since it uses as much as digits as its factorization.

21864227813 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 258048, while the sum is 44.

The spelling of 21864227813 in words is "twenty-one billion, eight hundred sixty-four million, two hundred twenty-seven thousand, eight hundred thirteen".