218447644440 has 128 divisors (see below), whose sum is σ = 660339993600. Its totient is φ = 57810001920.

The previous prime is 218447644439. The next prime is 218447644453. The reversal of 218447644440 is 44446744812.

It is a super-2 number, since 2×218447644440² (a number of 23 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (48) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 218447644440.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9692785 + ... + 9715295.

It is an arithmetic number, because the mean of its divisors is an integer number (5158906200).

Almost surely, 2^218447644440 is an apocalyptic number.

218447644440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 218447644440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (330169996800).

218447644440 is an abundant number, since it is smaller than the sum of its proper divisors (441892349160).

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

218447644440 is a wasteful number, since it uses less digits than its factorization.

218447644440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23137 (or 23133 counting only the distinct ones).

The product of its (nonzero) digits is 2752512, while the sum is 48.

The spelling of 218447644440 in words is "two hundred eighteen billion, four hundred forty-seven million, six hundred forty-four thousand, four hundred forty".