218290385 has 4 divisors (see below), whose sum is σ = 261948468. Its totient is φ = 174632304.

The previous prime is 218290361. The next prime is 218290399. The reversal of 218290385 is 583092812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 162996289 + 55294096 = 12767^2 + 7436^2 .

It is a cyclic number.

It is not a de Polignac number, because 218290385 - 2¹⁸ = 218028241 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21829034 + ... + 21829043.

It is an arithmetic number, because the mean of its divisors is an integer number (65487117).

Almost surely, 2^218290385 is an apocalyptic number.

It is an amenable number.

218290385 is a deficient number, since it is larger than the sum of its proper divisors (43658083).

218290385 is an equidigital number, since it uses as much as digits as its factorization.

218290385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43658082.

The product of its (nonzero) digits is 34560, while the sum is 38.

The square root of 218290385 is about 14774.6534646333. The cubic root of 218290385 is about 602.1132748952.

The spelling of 218290385 in words is "two hundred eighteen million, two hundred ninety thousand, three hundred eighty-five".