21843256543 has 2 divisors, whose sum is σ = 21843256544. Its totient is φ = 21843256542.

The previous prime is 21843256517. The next prime is 21843256559. The reversal of 21843256543 is 34565234812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21843256543 - 2¹⁷ = 21843125471 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21843256543.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21843256583) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10921628271 + 10921628272.

It is an arithmetic number, because the mean of its divisors is an integer number (10921628272).

Almost surely, 2^21843256543 is an apocalyptic number.

21843256543 is a deficient number, since it is larger than the sum of its proper divisors (1).

21843256543 is an equidigital number, since it uses as much as digits as its factorization.

21843256543 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 691200, while the sum is 43.

The spelling of 21843256543 in words is "twenty-one billion, eight hundred forty-three million, two hundred fifty-six thousand, five hundred forty-three".