18538945 has 4 divisors (see below), whose sum is σ = 22246740. Its totient is φ = 14831152.

The previous prime is 18538939. The next prime is 18538951. The reversal of 18538945 is 54983581.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54983581 = 167 ⋅329243.

It is an interprime number because it is at equal distance from previous prime (18538939) and next prime (18538951).

It can be written as a sum of positive squares in 2 ways, for example, as 2666689 + 15872256 = 1633^2 + 3984^2 .

It is a cyclic number.

It is not a de Polignac number, because 18538945 - 2¹¹ = 18536897 is a prime.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 1853890 + ... + 1853899.

It is an arithmetic number, because the mean of its divisors is an integer number (5561685).

Almost surely, 2^18538945 is an apocalyptic number.

It is an amenable number.

18538945 is a deficient number, since it is larger than the sum of its proper divisors (3707795).

18538945 is an equidigital number, since it uses as much as digits as its factorization.

18538945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3707794.

The product of its digits is 172800, while the sum is 43.

The square root of 18538945 is about 4305.6875176910. The cubic root of 18538945 is about 264.6640813054.

The spelling of 18538945 in words is "eighteen million, five hundred thirty-eight thousand, nine hundred forty-five".