1981355655168 has 286 divisors, whose sum is σ = 5944033322499. Its totient is φ = 660451885056.

The previous prime is 1981355655163. The next prime is 1981355655211. The reversal of 1981355655168 is 8615565531891.

It is a perfect power (a 5-th power), and thus also a powerful number.

It is a Jordan-Polya number, since it can be written as (4!)⁷ ⋅ (3!)³ ⋅ 2!.

1981355655168 is a `hidden beast` number, since 1 + 9 + 8 + 1 + 3 + 5 + 565 + 5 + 1 + 68 = 666.

It can be written as a sum of positive squares in only one way, i.e., 990677827584 + 990677827584 = 995328^2 + 995328^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=995328.

It is a super-3 number, since 3×1981355655168³ (a number of 38 digits) contains 333 as substring.

Its product of digits (38880000) is a multiple of the sum of its prime divisors (5).

It is not an unprimeable number, because it can be changed into a prime (1981355655163) by changing a digit.

It is a polite number, since it can be written in 10 ways as a sum of consecutive naturals, for example, 660451885055 + 660451885056 + 660451885057.

Almost surely, 2^{1981355655168} is an apocalyptic number.

1981355655168 is a gapful number since it is divisible by the number (18) 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 1981355655168

1981355655168 is an abundant number, since it is smaller than the sum of its proper divisors (3962677667331).

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

1981355655168 is an frugal number, since it uses more digits than its factorization.

1981355655168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80 (or 5 counting only the distinct ones).

The product of its digits is 38880000, while the sum is 63.

The spelling of 1981355655168 in words is "one trillion, nine hundred eighty-one billion, three hundred fifty-five million, six hundred fifty-five thousand, one hundred sixty-eight".