216641 has 2 divisors, whose sum is σ = 216642. Its totient is φ = 216640.

The previous prime is 216617. The next prime is 216647. The reversal of 216641 is 146612.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 211600 + 5041 = 460^2 + 71^2 .

It is a cyclic number.

It is not a de Polignac number, because 216641 - 2⁶ = 216577 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (216647) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108320 + 108321.

It is an arithmetic number, because the mean of its divisors is an integer number (108321).

2²¹⁶⁶⁴¹ is an apocalyptic number.

It is an amenable number.

216641 is a deficient number, since it is larger than the sum of its proper divisors (1).

216641 is an equidigital number, since it uses as much as digits as its factorization.

216641 is an evil number, because the sum of its binary digits is even.

The product of its digits is 288, while the sum is 20.

The square root of 216641 is about 465.4470968864. The cubic root of 216641 is about 60.0592932377.

The spelling of 216641 in words is "two hundred sixteen thousand, six hundred forty-one".