218440389 has 8 divisors (see below), whose sum is σ = 291435040. Its totient is φ = 145536336.

The previous prime is 218440379. The next prime is 218440403. The reversal of 218440389 is 983044812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 218440389 - 2⁴ = 218440373 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218440379) 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 in 7 ways as a sum of consecutive naturals, for example, 16807 + ... + 26820.

It is an arithmetic number, because the mean of its divisors is an integer number (36429380).

Almost surely, 2^218440389 is an apocalyptic number.

It is an amenable number.

218440389 is a deficient number, since it is larger than the sum of its proper divisors (72994651).

218440389 is a wasteful number, since it uses less digits than its factorization.

218440389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45299.

The product of its (nonzero) digits is 55296, while the sum is 39.

The square root of 218440389 is about 14779.7289893963. The cubic root of 218440389 is about 602.2511626590.

The spelling of 218440389 in words is "two hundred eighteen million, four hundred forty thousand, three hundred eighty-nine".