216929 has 4 divisors (see below), whose sum is σ = 221076. Its totient is φ = 212784.

The previous prime is 216919. The next prime is 216947. The reversal of 216929 is 929612.

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 123904 + 93025 = 352^2 + 305^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216929 is a prime.

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

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216919) 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, 1994 + ... + 2099.

It is an arithmetic number, because the mean of its divisors is an integer number (55269).

2²¹⁶⁹²⁹ is an apocalyptic number.

It is an amenable number.

216929 is a deficient number, since it is larger than the sum of its proper divisors (4147).

216929 is an equidigital number, since it uses as much as digits as its factorization.

216929 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4146.

The product of its digits is 1944, while the sum is 29.

The square root of 216929 is about 465.7563740841. The cubic root of 216929 is about 60.0858954926.

The spelling of 216929 in words is "two hundred sixteen thousand, nine hundred twenty-nine".