18644085400640 has 448 divisors, whose sum is σ = 54062019993600. Its totient is φ = 5978377912320.

The previous prime is 18644085400631. The next prime is 18644085400723. The reversal of 18644085400640 is 4600458044681.

It is a tau number, because it is divible by the number of its divisors (448).

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, 11601794717 + ... + 11601796323.

Almost surely, 2^{18644085400640} is an apocalyptic number.

18644085400640 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 18644085400640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27031009996800).

18644085400640 is an abundant number, since it is smaller than the sum of its proper divisors (35417934592960).

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

18644085400640 is a wasteful number, since it uses less digits than its factorization.

18644085400640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3378 (or 3368 counting only the distinct ones).

The product of its (nonzero) digits is 2949120, while the sum is 50.

The spelling of 18644085400640 in words is "eighteen trillion, six hundred forty-four billion, eighty-five million, four hundred thousand, six hundred forty".