18644444416 has 72 divisors (see below), whose sum is σ = 40223479464. Its totient is φ = 8574074880.

The previous prime is 18644444381. The next prime is 18644444417. The reversal of 18644444416 is 61444444681.

It can be written as a sum of positive squares in 4 ways, for example, as 231040000 + 18413404416 = 15200^2 + 135696^2 .

It is a super-3 number, since 3×18644444416³ (a number of 32 digits) contains 333 as substring.

It is a hoax number, since the sum of its digits (46) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18644444417) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 925200 + ... + 945136.

It is an arithmetic number, because the mean of its divisors is an integer number (558659437).

Almost surely, 2^18644444416 is an apocalyptic number.

18644444416 is a gapful number since it is divisible by the number (16) 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 18644444416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20111739732).

18644444416 is an abundant number, since it is smaller than the sum of its proper divisors (21579035048).

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

18644444416 is a wasteful number, since it uses less digits than its factorization.

18644444416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20247 (or 20233 counting only the distinct ones).

The product of its digits is 1179648, while the sum is 46.

It can be divided in two parts, 186444 and 44416, that added together give a triangular number (230860 = T₆₇₉).

The spelling of 18644444416 in words is "eighteen billion, six hundred forty-four million, four hundred forty-four thousand, four hundred sixteen".