216291 has 8 divisors (see below), whose sum is σ = 305424. Its totient is φ = 135680.

The previous prime is 216289. The next prime is 216317. The reversal of 216291 is 192612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 216291 - 2¹ = 216289 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 216291.

It is not an unprimeable number, because it can be changed into a prime (216211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2070 + ... + 2171.

It is an arithmetic number, because the mean of its divisors is an integer number (38178).

2²¹⁶²⁹¹ is an apocalyptic number.

216291 is a deficient number, since it is larger than the sum of its proper divisors (89133).

216291 is a wasteful number, since it uses less digits than its factorization.

216291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4261.

The product of its digits is 216, while the sum is 21.

The square root of 216291 is about 465.0709623273. The cubic root of 216291 is about 60.0269323534.

The spelling of 216291 in words is "two hundred sixteen thousand, two hundred ninety-one".