21744311957 has 2 divisors, whose sum is σ = 21744311958. Its totient is φ = 21744311956.

The previous prime is 21744311899. The next prime is 21744312011. The reversal of 21744311957 is 75911344712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16964802001 + 4779509956 = 130249^2 + 69134^2 .

It is a cyclic number.

It is not a de Polignac number, because 21744311957 - 2¹⁰ = 21744310933 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21744311657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10872155978 + 10872155979.

It is an arithmetic number, because the mean of its divisors is an integer number (10872155979).

Almost surely, 2^21744311957 is an apocalyptic number.

It is an amenable number.

21744311957 is a deficient number, since it is larger than the sum of its proper divisors (1).

21744311957 is an equidigital number, since it uses as much as digits as its factorization.

21744311957 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 211680, while the sum is 44.

The spelling of 21744311957 in words is "twenty-one billion, seven hundred forty-four million, three hundred eleven thousand, nine hundred fifty-seven".