218661444 has 60 divisors (see below), whose sum is σ = 573049708. Its totient is φ = 72705600.

The previous prime is 218661433. The next prime is 218661451. The reversal of 218661444 is 444166812.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 151585344 + 67076100 = 12312^2 + 8190^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 218661399 and 218661408.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 213654 + ... + 214674.

Almost surely, 2^218661444 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 218661444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (286524854).

218661444 is an abundant number, since it is smaller than the sum of its proper divisors (354388264).

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

218661444 is a wasteful number, since it uses less digits than its factorization.

218661444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1698 (or 1687 counting only the distinct ones).

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

The square root of 218661444 is about 14787.2054154935. The cubic root of 218661444 is about 602.4542474282.

The spelling of 218661444 in words is "two hundred eighteen million, six hundred sixty-one thousand, four hundred forty-four".