18345518 has 4 divisors (see below), whose sum is σ = 27518280. Its totient is φ = 9172758.

The previous prime is 18345517. The next prime is 18345527. The reversal of 18345518 is 81554381.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 81554381 = 6361 ⋅12821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18345517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4586378 + ... + 4586381.

It is an arithmetic number, because the mean of its divisors is an integer number (6879570).

Almost surely, 2^18345518 is an apocalyptic number.

18345518 is a deficient number, since it is larger than the sum of its proper divisors (9172762).

18345518 is an equidigital number, since it uses as much as digits as its factorization.

18345518 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9172761.

The product of its digits is 19200, while the sum is 35.

The square root of 18345518 is about 4283.1668190721. The cubic root of 18345518 is about 263.7403994619.

Adding to 18345518 its reverse (81554381), we get a palindrome (99899899).

The spelling of 18345518 in words is "eighteen million, three hundred forty-five thousand, five hundred eighteen".