216705 has 8 divisors (see below), whose sum is σ = 346752. Its totient is φ = 115568.

The previous prime is 216703. The next prime is 216719. The reversal of 216705 is 507612.

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 216705 - 2¹ = 216703 is a prime.

It is a super-2 number, since 2×216705² = 93922114050, which contains 22 as substring.

It is an Ulam number.

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

It is a nialpdrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (216703) 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, 7209 + ... + 7238.

It is an arithmetic number, because the mean of its divisors is an integer number (43344).

2²¹⁶⁷⁰⁵ is an apocalyptic number.

It is an amenable number.

216705 is a deficient number, since it is larger than the sum of its proper divisors (130047).

216705 is a wasteful number, since it uses less digits than its factorization.

216705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14455.

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 216705 is about 465.5158429098. The cubic root of 216705 is about 60.0652068865.

The spelling of 216705 in words is "two hundred sixteen thousand, seven hundred five".