218781438 has 32 divisors (see below), whose sum is σ = 444934176. Its totient is φ = 71705088.

The previous prime is 218781419. The next prime is 218781439. The reversal of 218781438 is 834187812.

It is a super-2 number, since 2×218781438² = 95730635226695688, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a self number, because there is not a number n which added to its sum of digits gives 218781438.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218781439) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 199620 + ... + 200712.

It is an arithmetic number, because the mean of its divisors is an integer number (13904193).

Almost surely, 2^218781438 is an apocalyptic number.

218781438 is an abundant number, since it is smaller than the sum of its proper divisors (226152738).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

218781438 is a wasteful number, since it uses less digits than its factorization.

218781438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1628.

The product of its digits is 86016, while the sum is 42.

The square root of 218781438 is about 14791.2622179448. The cubic root of 218781438 is about 602.5644294430.

The spelling of 218781438 in words is "two hundred eighteen million, seven hundred eighty-one thousand, four hundred thirty-eight".