18943978893840 has 4320 divisors, whose sum is σ = 93126624514560. Its totient is φ = 3543079034880.

The previous prime is 18943978893821. The next prime is 18943978893871. The reversal of 18943978893840 is 4839887934981.

18943978893840 is a `hidden beast` number, since 1 + 8 + 9 + 439 + 78 + 89 + 38 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a self number, because there is not a number n which added to its sum of digits gives 18943978893840.

It is an unprimeable number.

It is a polite number, since it can be written in 863 ways as a sum of consecutive naturals, for example, 70423713226 + ... + 70423713494.

It is an arithmetic number, because the mean of its divisors is an integer number (21557089008).

Almost surely, 2^{18943978893840} is an apocalyptic number.

18943978893840 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 18943978893840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46563312257280).

18943978893840 is an abundant number, since it is smaller than the sum of its proper divisors (74182645620720).

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

18943978893840 is a wasteful number, since it uses less digits than its factorization.

18943978893840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 393 (or 357 counting only the distinct ones).

The product of its (nonzero) digits is 3009871872, while the sum is 81.

The spelling of 18943978893840 in words is "eighteen trillion, nine hundred forty-three billion, nine hundred seventy-eight million, eight hundred ninety-three thousand, eight hundred forty".