216423321 has 4 divisors (see below), whose sum is σ = 288564432. Its totient is φ = 144282212.

The previous prime is 216423313. The next prime is 216423349. The reversal of 216423321 is 123324612.

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 216423321 - 2³ = 216423313 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 216423291 and 216423300.

It is not an unprimeable number, because it can be changed into a prime (216423301) 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, 36070551 + ... + 36070556.

It is an arithmetic number, because the mean of its divisors is an integer number (72141108).

Almost surely, 2^216423321 is an apocalyptic number.

It is an amenable number.

216423321 is a deficient number, since it is larger than the sum of its proper divisors (72141111).

216423321 is an equidigital number, since it uses as much as digits as its factorization.

216423321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72141110.

The product of its digits is 1728, while the sum is 24.

The square root of 216423321 is about 14711.3330803160. Note that the first 3 decimals coincide. The cubic root of 216423321 is about 600.3917081078.

Adding to 216423321 its reverse (123324612), we get a palindrome (339747933).

The spelling of 216423321 in words is "two hundred sixteen million, four hundred twenty-three thousand, three hundred twenty-one".