18940321 has 4 divisors (see below), whose sum is σ = 19937200. Its totient is φ = 17943444.

The previous prime is 18940309. The next prime is 18940333. The reversal of 18940321 is 12304981.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (18940309) and next prime (18940333).

It is a cyclic number.

It is not a de Polignac number, because 18940321 - 2¹¹ = 18938273 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18940321.

It is not an unprimeable number, because it can be changed into a prime (18947321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 498411 + ... + 498448.

It is an arithmetic number, because the mean of its divisors is an integer number (4984300).

Almost surely, 2^18940321 is an apocalyptic number.

It is an amenable number.

18940321 is a deficient number, since it is larger than the sum of its proper divisors (996879).

18940321 is an equidigital number, since it uses as much as digits as its factorization.

18940321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 996878.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 18940321 is about 4352.0479087437. The cubic root of 18940321 is about 266.5604901955.

The spelling of 18940321 in words is "eighteen million, nine hundred forty thousand, three hundred twenty-one".