21946864913 has 2 divisors, whose sum is σ = 21946864914. Its totient is φ = 21946864912.

The previous prime is 21946864903. The next prime is 21946864967. The reversal of 21946864913 is 31946864912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21918210304 + 28654609 = 148048^2 + 5353^2 .

It is a cyclic number.

It is not a de Polignac number, because 21946864913 - 2⁸ = 21946864657 is a prime.

It is not a weakly prime, because it can be changed into another prime (21946864903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10973432456 + 10973432457.

It is an arithmetic number, because the mean of its divisors is an integer number (10973432457).

Almost surely, 2^21946864913 is an apocalyptic number.

It is an amenable number.

21946864913 is a deficient number, since it is larger than the sum of its proper divisors (1).

21946864913 is an equidigital number, since it uses as much as digits as its factorization.

21946864913 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2239488, while the sum is 53.

Subtracting 21946864913 from its reverse (31946864912), we obtain a palindrome (9999999999).

The spelling of 21946864913 in words is "twenty-one billion, nine hundred forty-six million, eight hundred sixty-four thousand, nine hundred thirteen".