21864110813 has 2 divisors, whose sum is σ = 21864110814. Its totient is φ = 21864110812.

The previous prime is 21864110747. The next prime is 21864110861. The reversal of 21864110813 is 31801146812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20546928964 + 1317181849 = 143342^2 + 36293^2 .

It is a cyclic number.

It is not a de Polignac number, because 21864110813 - 2²⁸ = 21595675357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21864110113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10932055406 + 10932055407.

It is an arithmetic number, because the mean of its divisors is an integer number (10932055407).

Almost surely, 2^21864110813 is an apocalyptic number.

It is an amenable number.

21864110813 is a deficient number, since it is larger than the sum of its proper divisors (1).

21864110813 is an equidigital number, since it uses as much as digits as its factorization.

21864110813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9216, while the sum is 35.

The spelling of 21864110813 in words is "twenty-one billion, eight hundred sixty-four million, one hundred ten thousand, eight hundred thirteen".