18273989 has 4 divisors (see below), whose sum is σ = 18326700. Its totient is φ = 18221280.

The previous prime is 18273979. The next prime is 18274037. The reversal of 18273989 is 98937281.

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

It can be written as a sum of positive squares in 2 ways, for example, as 6543364 + 11730625 = 2558^2 + 3425^2 .

It is a cyclic number.

It is not a de Polignac number, because 18273989 - 2¹² = 18269893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18273919) 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, 25832 + ... + 26529.

It is an arithmetic number, because the mean of its divisors is an integer number (4581675).

Almost surely, 2^18273989 is an apocalyptic number.

It is an amenable number.

18273989 is a deficient number, since it is larger than the sum of its proper divisors (52711).

18273989 is an equidigital number, since it uses as much as digits as its factorization.

18273989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52710.

The product of its digits is 217728, while the sum is 47.

The square root of 18273989 is about 4274.8086506884. The cubic root of 18273989 is about 263.3971792351.

The spelling of 18273989 in words is "eighteen million, two hundred seventy-three thousand, nine hundred eighty-nine".