216866 has 16 divisors (see below), whose sum is σ = 369600. Its totient is φ = 94608.

The previous prime is 216859. The next prime is 216877. The reversal of 216866 is 668612.

216866 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 275 + ... + 713.

It is an arithmetic number, because the mean of its divisors is an integer number (23100).

2²¹⁶⁸⁶⁶ is an apocalyptic number.

216866 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

216866 is a deficient number, since it is larger than the sum of its proper divisors (152734).

216866 is a wasteful number, since it uses less digits than its factorization.

216866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 473.

The product of its digits is 3456, while the sum is 29.

The square root of 216866 is about 465.6887372484. The cubic root of 216866 is about 60.0800782622.

The spelling of 216866 in words is "two hundred sixteen thousand, eight hundred sixty-six".