218971 has 2 divisors, whose sum is σ = 218972. Its totient is φ = 218970.

The previous prime is 218969. The next prime is 218987. The reversal of 218971 is 179812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 218971 - 2¹ = 218969 is a prime.

Together with 218969, it forms a pair of twin primes.

218971 is a lucky number.

It is a plaindrome in base 13.

It is not a weakly prime, because it can be changed into another prime (218941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109485 + 109486.

It is an arithmetic number, because the mean of its divisors is an integer number (109486).

2²¹⁸⁹⁷¹ is an apocalyptic number.

218971 is a deficient number, since it is larger than the sum of its proper divisors (1).

218971 is an equidigital number, since it uses as much as digits as its factorization.

218971 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1008, while the sum is 28.

The square root of 218971 is about 467.9433726425. The cubic root of 218971 is about 60.2738408774.

The spelling of 218971 in words is "two hundred eighteen thousand, nine hundred seventy-one".