216231 has 4 divisors (see below), whose sum is σ = 288312. Its totient is φ = 144152.

The previous prime is 216217. The next prime is 216233. The reversal of 216231 is 132612.

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

It is a cyclic number.

It is not a de Polignac number, because 216231 - 2⁷ = 216103 is a prime.

It is a super-2 number, since 2×216231² = 93511690722, which contains 22 as substring.

It is a D-number.

It is a self number, because there is not a number n which added to its sum of digits gives 216231.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216233) 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, 36036 + ... + 36041.

It is an arithmetic number, because the mean of its divisors is an integer number (72078).

2²¹⁶²³¹ is an apocalyptic number.

216231 is a deficient number, since it is larger than the sum of its proper divisors (72081).

216231 is an equidigital number, since it uses as much as digits as its factorization.

216231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72080.

The product of its digits is 72, while the sum is 15.

The square root of 216231 is about 465.0064515681. The cubic root of 216231 is about 60.0213812687.

Adding to 216231 its reverse (132612), we get a palindrome (348843).

The spelling of 216231 in words is "two hundred sixteen thousand, two hundred thirty-one".