18439981560 has 1024 divisors, whose sum is σ = 84942950400. Its totient is φ = 3433881600.

The previous prime is 18439981559. The next prime is 18439981579. The reversal of 18439981560 is 6518993481.

18439981560 is a `hidden beast` number, since 184 + 399 + 8 + 15 + 60 = 666.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a junction number, because it is equal to n+sod(n) for n = 18439981497 and 18439981506.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 39999730 + ... + 40000190.

It is an arithmetic number, because the mean of its divisors is an integer number (82952100).

Almost surely, 2^18439981560 is an apocalyptic number.

18439981560 is a gapful number since it is divisible by the number (10) 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 18439981560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42471475200).

18439981560 is an abundant number, since it is smaller than the sum of its proper divisors (66502968840).

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

18439981560 is a wasteful number, since it uses less digits than its factorization.

18439981560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 549 (or 539 counting only the distinct ones).

The product of its (nonzero) digits is 1866240, while the sum is 54.

It can be divided in two parts, 18439 and 981560, that added together give a palindrome (999999).

The spelling of 18439981560 in words is "eighteen billion, four hundred thirty-nine million, nine hundred eighty-one thousand, five hundred sixty".