1981816543413 has 32 divisors (see below), whose sum is σ = 3471161990400. Its totient is φ = 1093416020928.

The previous prime is 1981816543411. The next prime is 1981816543423. The reversal of 1981816543413 is 3143456181891.

1981816543413 is a `hidden beast` number, since 1 + 9 + 8 + 1 + 81 + 6 + 543 + 4 + 13 = 666.

It is not a de Polignac number, because 1981816543413 - 2¹ = 1981816543411 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1981816543413.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981816543411) by changing a digit.

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, 180784206 + ... + 180795167.

It is an arithmetic number, because the mean of its divisors is an integer number (108473812200).

Almost surely, 2^{1981816543413} is an apocalyptic number.

It is an amenable number.

1981816543413 is a deficient number, since it is larger than the sum of its proper divisors (1489345446987).

1981816543413 is a wasteful number, since it uses less digits than its factorization.

1981816543413 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 361579418 (or 361579412 counting only the distinct ones).

The product of its digits is 2488320, while the sum is 54.

The spelling of 1981816543413 in words is "one trillion, nine hundred eighty-one billion, eight hundred sixteen million, five hundred forty-three thousand, four hundred thirteen".