18409543 has 2 divisors, whose sum is σ = 18409544. Its totient is φ = 18409542.

The previous prime is 18409541. The next prime is 18409549. The reversal of 18409543 is 34590481.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18409543 - 2¹ = 18409541 is a prime.

It is a super-2 number, since 2×18409543² = 677822546937698, which contains 22 as substring.

Together with 18409541, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 18409499 and 18409508.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18409541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9204771 + 9204772.

It is an arithmetic number, because the mean of its divisors is an integer number (9204772).

Almost surely, 2^18409543 is an apocalyptic number.

18409543 is a deficient number, since it is larger than the sum of its proper divisors (1).

18409543 is an equidigital number, since it uses as much as digits as its factorization.

18409543 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 18409543 is about 4290.6343353868. The cubic root of 18409543 is about 264.0468571175.

The spelling of 18409543 in words is "eighteen million, four hundred nine thousand, five hundred forty-three".