218423 has 2 divisors, whose sum is σ = 218424. Its totient is φ = 218422.

The previous prime is 218419. The next prime is 218437. The reversal of 218423 is 324812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 218423 - 2² = 218419 is a prime.

It is a super-4 number, since 4×218423⁴ (a number of 22 digits) contains 4444 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 218395 and 218404.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218453) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109211 + 109212.

It is an arithmetic number, because the mean of its divisors is an integer number (109212).

2²¹⁸⁴²³ is an apocalyptic number.

218423 is a deficient number, since it is larger than the sum of its proper divisors (1).

218423 is an equidigital number, since it uses as much as digits as its factorization.

218423 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 384, while the sum is 20.

The square root of 218423 is about 467.3574649024. The cubic root of 218423 is about 60.2235181452.

The spelling of 218423 in words is "two hundred eighteen thousand, four hundred twenty-three".