216261 has 6 divisors (see below), whose sum is σ = 312390. Its totient is φ = 144168.

The previous prime is 216259. The next prime is 216263. The reversal of 216261 is 162612.

It is a happy number.

216261 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (216259) and next prime (216263).

It can be written as a sum of positive squares in only one way, i.e., 216225 + 36 = 465^2 + 6^2 .

It is not a de Polignac number, because 216261 - 2¹ = 216259 is a prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 216261.

It is not an unprimeable number, because it can be changed into a prime (216263) 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, 12006 + ... + 12023.

It is an arithmetic number, because the mean of its divisors is an integer number (52065).

2²¹⁶²⁶¹ is an apocalyptic number.

It is an amenable number.

216261 is a deficient number, since it is larger than the sum of its proper divisors (96129).

216261 is a wasteful number, since it uses less digits than its factorization.

216261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24035 (or 24032 counting only the distinct ones).

The product of its digits is 144, while the sum is 18.

The square root of 216261 is about 465.0387080663. The cubic root of 216261 is about 60.0241569394.

Adding to 216261 its reverse (162612), we get a palindrome (378873).

The spelling of 216261 in words is "two hundred sixteen thousand, two hundred sixty-one".