21744143 has 2 divisors, whose sum is σ = 21744144. Its totient is φ = 21744142.

The previous prime is 21744137. The next prime is 21744157. The reversal of 21744143 is 34144712.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21744143 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21744193) 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, 10872071 + 10872072.

It is an arithmetic number, because the mean of its divisors is an integer number (10872072).

Almost surely, 2^21744143 is an apocalyptic number.

21744143 is a deficient number, since it is larger than the sum of its proper divisors (1).

21744143 is an equidigital number, since it uses as much as digits as its factorization.

21744143 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2688, while the sum is 26.

The square root of 21744143 is about 4663.0615479532. The cubic root of 21744143 is about 279.1134501765.

Adding to 21744143 its reverse (34144712), we get a palindrome (55888855).

The spelling of 21744143 in words is "twenty-one million, seven hundred forty-four thousand, one hundred forty-three".