18409243 has 4 divisors (see below), whose sum is σ = 18581400. Its totient is φ = 18237088.

The previous prime is 18409241. The next prime is 18409247. The reversal of 18409243 is 34290481.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34290481 = 1471 ⋅23311.

It is a cyclic number.

It is not a de Polignac number, because 18409243 - 2¹ = 18409241 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18409241) 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 in 3 ways as a sum of consecutive naturals, for example, 85918 + ... + 86131.

It is an arithmetic number, because the mean of its divisors is an integer number (4645350).

Almost surely, 2^18409243 is an apocalyptic number.

18409243 is a deficient number, since it is larger than the sum of its proper divisors (172157).

18409243 is a wasteful number, since it uses less digits than its factorization.

18409243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172156.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 18409243 is about 4290.5993753787. The cubic root of 18409243 is about 264.0454228164.

The spelling of 18409243 in words is "eighteen million, four hundred nine thousand, two hundred forty-three".