216871 has 4 divisors (see below), whose sum is σ = 218592. Its totient is φ = 215152.

The previous prime is 216859. The next prime is 216877. The reversal of 216871 is 178612.

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 216871 - 2⁷ = 216743 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216877) 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, 655 + ... + 928.

It is an arithmetic number, because the mean of its divisors is an integer number (54648).

2²¹⁶⁸⁷¹ is an apocalyptic number.

216871 is a deficient number, since it is larger than the sum of its proper divisors (1721).

216871 is a wasteful number, since it uses less digits than its factorization.

216871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1720.

The product of its digits is 672, while the sum is 25.

The square root of 216871 is about 465.6941056101. The cubic root of 216871 is about 60.0805399883.

The spelling of 216871 in words is "two hundred sixteen thousand, eight hundred seventy-one".