218430321 has 4 divisors (see below), whose sum is σ = 291240432. Its totient is φ = 145620212.

The previous prime is 218430313. The next prime is 218430337. The reversal of 218430321 is 123034812.

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 a cyclic number.

It is not a de Polignac number, because 218430321 - 2³ = 218430313 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 218430291 and 218430300.

It is not an unprimeable number, because it can be changed into a prime (218430301) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36405051 + ... + 36405056.

It is an arithmetic number, because the mean of its divisors is an integer number (72810108).

Almost surely, 2^218430321 is an apocalyptic number.

It is an amenable number.

218430321 is a deficient number, since it is larger than the sum of its proper divisors (72810111).

218430321 is an equidigital number, since it uses as much as digits as its factorization.

218430321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72810110.

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 218430321 is about 14779.3883838270. The cubic root of 218430321 is about 602.2419098557.

The spelling of 218430321 in words is "two hundred eighteen million, four hundred thirty thousand, three hundred twenty-one".