218644416 has 84 divisors (see below), whose sum is σ = 630734832. Its totient is φ = 72413184.

The previous prime is 218644411. The next prime is 218644453. The reversal of 218644416 is 614446812.

It is a happy number.

218644416 is a `hidden beast` number, since 2 + 1 + 8 + 644 + 4 + 1 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218644411) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 95056 + ... + 97328.

It is an arithmetic number, because the mean of its divisors is an integer number (7508748).

Almost surely, 2^218644416 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 218644416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (315367416).

218644416 is an abundant number, since it is smaller than the sum of its proper divisors (412090416).

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

218644416 is a wasteful number, since it uses less digits than its factorization.

218644416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2458 (or 2445 counting only the distinct ones).

The product of its digits is 36864, while the sum is 36.

The square root of 218644416 is about 14786.6296362626. The cubic root of 218644416 is about 602.4386085528.

The spelling of 218644416 in words is "two hundred eighteen million, six hundred forty-four thousand, four hundred sixteen".