18415544640 has 224 divisors, whose sum is σ = 60597166080. Its totient is φ = 4735051776.

The previous prime is 18415544639. The next prime is 18415544663. The reversal of 18415544640 is 4644551481.

It is a junction number, because it is equal to n+sod(n) for n = 18415544592 and 18415544601.

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, 3258297 + ... + 3263943.

Almost surely, 2^18415544640 is an apocalyptic number.

18415544640 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 18415544640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30298583040).

18415544640 is an abundant number, since it is smaller than the sum of its proper divisors (42181621440).

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

18415544640 is a wasteful number, since it uses less digits than its factorization.

18415544640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5789 (or 5779 counting only the distinct ones).

The product of its (nonzero) digits is 307200, while the sum is 42.

The spelling of 18415544640 in words is "eighteen billion, four hundred fifteen million, five hundred forty-four thousand, six hundred forty".