216109 has 4 divisors (see below), whose sum is σ = 217404. Its totient is φ = 214816.

The previous prime is 216107. The next prime is 216113. The reversal of 216109 is 901612.

216109 is nontrivially palindromic in base 14.

216109 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in 2 ways, for example, as 152100 + 64009 = 390^2 + 253^2 .

It is a cyclic number.

It is not a de Polignac number, because 216109 - 2¹ = 216107 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216103) 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, 352 + ... + 745.

It is an arithmetic number, because the mean of its divisors is an integer number (54351).

2²¹⁶¹⁰⁹ is an apocalyptic number.

It is an amenable number.

216109 is a deficient number, since it is larger than the sum of its proper divisors (1295).

216109 is a wasteful number, since it uses less digits than its factorization.

216109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1294.

The product of its (nonzero) digits is 108, while the sum is 19.

The square root of 216109 is about 464.8752520838. The cubic root of 216109 is about 60.0100908954.

It can be divided in two parts, 216 and 109, that added together give a triangular number (325 = T₂₅).

The spelling of 216109 in words is "two hundred sixteen thousand, one hundred nine".