18509938 has 8 divisors (see below), whose sum is σ = 27809388. Its totient is φ = 9240144.

The previous prime is 18509929. The next prime is 18509941. The reversal of 18509938 is 83990581.

It can be written as a sum of positive squares in 2 ways, for example, as 18429849 + 80089 = 4293^2 + 283^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 18509894 and 18509903.

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, 5781 + ... + 8392.

Almost surely, 2^18509938 is an apocalyptic number.

18509938 is a deficient number, since it is larger than the sum of its proper divisors (9299450).

18509938 is a wasteful number, since it uses less digits than its factorization.

18509938 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14828.

The product of its (nonzero) digits is 77760, while the sum is 43.

The square root of 18509938 is about 4302.3177474473. The cubic root of 18509938 is about 264.5259735096.

The spelling of 18509938 in words is "eighteen million, five hundred nine thousand, nine hundred thirty-eight".