1991838534912 has 432 divisors, whose sum is σ = 6049946972160. Its totient is φ = 629665075200.

The previous prime is 1991838534901. The next prime is 1991838534923. The reversal of 1991838534912 is 2194358381991.

1991838534912 is a `hidden beast` number, since 1 + 9 + 9 + 1 + 8 + 3 + 8 + 534 + 91 + 2 = 666.

It is an interprime number because it is at equal distance from previous prime (1991838534901) and next prime (1991838534923).

It is a super-3 number, since 3×1991838534912³ (a number of 38 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1991838534912.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 453616237 + ... + 453620627.

It is an arithmetic number, because the mean of its divisors is an integer number (14004506880).

Almost surely, 2^{1991838534912} is an apocalyptic number.

1991838534912 is a gapful number since it is divisible by the number (12) 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 1991838534912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3024973486080).

1991838534912 is an abundant number, since it is smaller than the sum of its proper divisors (4058108437248).

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

1991838534912 is a wasteful number, since it uses less digits than its factorization.

1991838534912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4590 (or 4573 counting only the distinct ones).

The product of its digits is 16796160, while the sum is 63.

The spelling of 1991838534912 in words is "one trillion, nine hundred ninety-one billion, eight hundred thirty-eight million, five hundred thirty-four thousand, nine hundred twelve".