18404321 has 16 divisors (see below), whose sum is σ = 20357568. Its totient is φ = 16536000.

The previous prime is 18404317. The next prime is 18404327. The reversal of 18404321 is 12340481.

It is not a de Polignac number, because 18404321 - 2² = 18404317 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18404327) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 140426 + ... + 140556.

It is an arithmetic number, because the mean of its divisors is an integer number (1272348).

Almost surely, 2^18404321 is an apocalyptic number.

It is an amenable number.

18404321 is a deficient number, since it is larger than the sum of its proper divisors (1953247).

18404321 is a wasteful number, since it uses less digits than its factorization.

18404321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 352.

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 18404321 is about 4290.0257574984. The cubic root of 18404321 is about 264.0218884897.

The spelling of 18404321 in words is "eighteen million, four hundred four thousand, three hundred twenty-one".