218649 has 4 divisors (see below), whose sum is σ = 291536. Its totient is φ = 145764.

The previous prime is 218641. The next prime is 218651. The reversal of 218649 is 946812.

218649 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 218649 - 2³ = 218641 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (218641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36439 + ... + 36444.

It is an arithmetic number, because the mean of its divisors is an integer number (72884).

2²¹⁸⁶⁴⁹ is an apocalyptic number.

It is an amenable number.

218649 is a deficient number, since it is larger than the sum of its proper divisors (72887).

218649 is an equidigital number, since it uses as much as digits as its factorization.

218649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72886.

The product of its digits is 3456, while the sum is 30.

The square root of 218649 is about 467.5991873389. The cubic root of 218649 is about 60.2442818675.

The spelling of 218649 in words is "two hundred eighteen thousand, six hundred forty-nine".