216671705 has 4 divisors (see below), whose sum is σ = 260006052. Its totient is φ = 173337360.

The previous prime is 216671701. The next prime is 216671723. The reversal of 216671705 is 507176612.

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 31058329 + 185613376 = 5573^2 + 13624^2 .

It is not a de Polignac number, because 216671705 - 2² = 216671701 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216671701) 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, 21667166 + ... + 21667175.

It is an arithmetic number, because the mean of its divisors is an integer number (65001513).

Almost surely, 2^216671705 is an apocalyptic number.

It is an amenable number.

216671705 is a deficient number, since it is larger than the sum of its proper divisors (43334347).

216671705 is an equidigital number, since it uses as much as digits as its factorization.

216671705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43334346.

The product of its (nonzero) digits is 17640, while the sum is 35.

The square root of 216671705 is about 14719.7725865585. The cubic root of 216671705 is about 600.6213054845.

The spelling of 216671705 in words is "two hundred sixteen million, six hundred seventy-one thousand, seven hundred five".