1781993868815 has 8 divisors (see below), whose sum is σ = 2138640681408. Its totient is φ = 1425429735840.

The previous prime is 1781993868803. The next prime is 1781993868821. The reversal of 1781993868815 is 5188683991871.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1781993868815 - 2⁴⁰ = 682482241039 is a prime.

It is a Duffinian number.

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 7 ways as a sum of consecutive naturals, for example, 20622476 + ... + 20708705.

It is an arithmetic number, because the mean of its divisors is an integer number (267330085176).

Almost surely, 2^{1781993868815} is an apocalyptic number.

1781993868815 is a deficient number, since it is larger than the sum of its proper divisors (356646812593).

1781993868815 is an equidigital number, since it uses as much as digits as its factorization.

1781993868815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41339809.

The product of its digits is 209018880, while the sum is 74.

The spelling of 1781993868815 in words is "one trillion, seven hundred eighty-one billion, nine hundred ninety-three million, eight hundred sixty-eight thousand, eight hundred fifteen".