1991793403281 has 16 divisors (see below), whose sum is σ = 2898762763968. Its totient is φ = 1206477216000.

The previous prime is 1991793403273. The next prime is 1991793403283. The reversal of 1991793403281 is 1823043971991.

It is a happy number.

It is not a de Polignac number, because 1991793403281 - 2³ = 1991793403273 is a prime.

It is a super-2 number, since 2×1991793403281² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1991793403283) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16697196 + ... + 16816061.

It is an arithmetic number, because the mean of its divisors is an integer number (181172672748).

Almost surely, 2^{1991793403281} is an apocalyptic number.

1991793403281 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1991793403281 is a deficient number, since it is larger than the sum of its proper divisors (906969360687).

1991793403281 is a wasteful number, since it uses less digits than its factorization.

1991793403281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33515072.

The product of its (nonzero) digits is 2939328, while the sum is 57.

The spelling of 1991793403281 in words is "one trillion, nine hundred ninety-one billion, seven hundred ninety-three million, four hundred three thousand, two hundred eighty-one".