18640684440 has 256 divisors, whose sum is σ = 72745344000. Its totient is φ = 4156738560.

The previous prime is 18640684411. The next prime is 18640684453. The reversal of 18640684440 is 4448604681.

It is a super-2 number, since 2×18640684440² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 279891 + ... + 340029.

It is an arithmetic number, because the mean of its divisors is an integer number (284161500).

Almost surely, 2^18640684440 is an apocalyptic number.

18640684440 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 18640684440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36372672000).

18640684440 is an abundant number, since it is smaller than the sum of its proper divisors (54104659560).

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

18640684440 is a wasteful number, since it uses less digits than its factorization.

18640684440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60207 (or 60197 counting only the distinct ones).

The product of its (nonzero) digits is 589824, while the sum is 45.

The spelling of 18640684440 in words is "eighteen billion, six hundred forty million, six hundred eighty-four thousand, four hundred forty".