216632321 has 4 divisors (see below), whose sum is σ = 217048644. Its totient is φ = 216216000.

The previous prime is 216632263. The next prime is 216632329. The reversal of 216632321 is 123236612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 22420225 + 194212096 = 4735^2 + 13936^2 .

It is a cyclic number.

It is not a de Polignac number, because 216632321 - 2¹⁴ = 216615937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216632329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 207380 + ... + 208421.

It is an arithmetic number, because the mean of its divisors is an integer number (54262161).

Almost surely, 2^216632321 is an apocalyptic number.

It is an amenable number.

216632321 is a deficient number, since it is larger than the sum of its proper divisors (416323).

216632321 is an equidigital number, since it uses as much as digits as its factorization.

216632321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 416322.

The product of its digits is 2592, while the sum is 26.

The square root of 216632321 is about 14718.4347333540. The cubic root of 216632321 is about 600.5849120187.

Adding to 216632321 its reverse (123236612), we get a palindrome (339868933).

The spelling of 216632321 in words is "two hundred sixteen million, six hundred thirty-two thousand, three hundred twenty-one".