18210321 has 6 divisors (see below), whose sum is σ = 26303810. Its totient is φ = 12140208.

The previous prime is 18210317. The next prime is 18210329. The reversal of 18210321 is 12301281.

It can be written as a sum of positive squares in only one way, i.e., 13950225 + 4260096 = 3735^2 + 2064^2 .

It is not a de Polignac number, because 18210321 - 2² = 18210317 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18210294 and 18210303.

It is not an unprimeable number, because it can be changed into a prime (18210329) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1011676 + ... + 1011693.

Almost surely, 2^18210321 is an apocalyptic number.

It is an amenable number.

18210321 is a deficient number, since it is larger than the sum of its proper divisors (8093489).

18210321 is a wasteful number, since it uses less digits than its factorization.

18210321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2023375 (or 2023372 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 18210321 is about 4267.3552699535. The cubic root of 18210321 is about 263.0909245296.

The spelling of 18210321 in words is "eighteen million, two hundred ten thousand, three hundred twenty-one".