216571 has 2 divisors, whose sum is σ = 216572. Its totient is φ = 216570.

The previous prime is 216569. The next prime is 216577. The reversal of 216571 is 175612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 216571 - 2¹ = 216569 is a prime.

Together with 216569, it forms a pair of twin primes.

It is a nialpdrome in base 13.

It is not a weakly prime, because it can be changed into another prime (216577) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108285 + 108286.

It is an arithmetic number, because the mean of its divisors is an integer number (108286).

2²¹⁶⁵⁷¹ is an apocalyptic number.

216571 is a deficient number, since it is larger than the sum of its proper divisors (1).

216571 is an equidigital number, since it uses as much as digits as its factorization.

216571 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 420, while the sum is 22.

The square root of 216571 is about 465.3718942953. The cubic root of 216571 is about 60.0528238507.

It can be divided in two parts, 216 and 571, that added together give a palindrome (787).

The spelling of 216571 in words is "two hundred sixteen thousand, five hundred seventy-one".