18236506 has 4 divisors (see below), whose sum is σ = 27354762. Its totient is φ = 9118252.

The previous prime is 18236503. The next prime is 18236509. The reversal of 18236506 is 60563281.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (18236503) and next prime (18236509).

It can be written as a sum of positive squares in only one way, i.e., 15484225 + 2752281 = 3935^2 + 1659^2 .

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 not an unprimeable number, because it can be changed into a prime (18236501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4559125 + ... + 4559128.

Almost surely, 2^18236506 is an apocalyptic number.

18236506 is a deficient number, since it is larger than the sum of its proper divisors (9118256).

18236506 is an equidigital number, since it uses as much as digits as its factorization.

18236506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9118255.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 18236506 is about 4270.4222273682. The cubic root of 18236506 is about 263.2169654440.

Adding to 18236506 its reverse (60563281), we get a palindrome (78799787).

The spelling of 18236506 in words is "eighteen million, two hundred thirty-six thousand, five hundred six".