217643 has 2 divisors, whose sum is σ = 217644. Its totient is φ = 217642.

The previous prime is 217619. The next prime is 217661. The reversal of 217643 is 346712.

217643 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 217643 - 2⁶ = 217579 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (210643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108821 + 108822.

It is an arithmetic number, because the mean of its divisors is an integer number (108822).

2²¹⁷⁶⁴³ is an apocalyptic number.

217643 is a deficient number, since it is larger than the sum of its proper divisors (1).

217643 is an equidigital number, since it uses as much as digits as its factorization.

217643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1008, while the sum is 23.

The square root of 217643 is about 466.5222395556. The cubic root of 217643 is about 60.1517455277.

The spelling of 217643 in words is "two hundred seventeen thousand, six hundred forty-three".