1981743613605 has 32 divisors (see below), whose sum is σ = 4026399724800. Its totient is φ = 905939937216.

The previous prime is 1981743613463. The next prime is 1981743613643. The reversal of 1981743613605 is 5063163471891.

1981743613605 is a `hidden beast` number, since 1 + 9 + 8 + 17 + 4 + 3 + 6 + 13 + 605 = 666.

It is not a de Polignac number, because 1981743613605 - 2⁸ = 1981743613349 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1048540650 + ... + 1048542539.

It is an arithmetic number, because the mean of its divisors is an integer number (125824991400).

Almost surely, 2^{1981743613605} is an apocalyptic number.

1981743613605 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1981743613605 is an abundant number, since it is smaller than the sum of its proper divisors (2044656111195).

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

1981743613605 is a wasteful number, since it uses less digits than its factorization.

1981743613605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2097083210 (or 2097083204 counting only the distinct ones).

The product of its (nonzero) digits is 3265920, while the sum is 54.

The spelling of 1981743613605 in words is "one trillion, nine hundred eighty-one billion, seven hundred forty-three million, six hundred thirteen thousand, six hundred five".