1981401443611 has 2 divisors, whose sum is σ = 1981401443612. Its totient is φ = 1981401443610.

The previous prime is 1981401443599. The next prime is 1981401443657. The reversal of 1981401443611 is 1163441041891.

It is a weak prime.

It is an emirp because it is prime and its reverse (1163441041891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1981401443611 - 2²³ = 1981393055003 is a prime.

It is a super-3 number, since 3×1981401443611³ (a number of 38 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (1981401443911) 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 as a sum of consecutive naturals, namely, 990700721805 + 990700721806.

It is an arithmetic number, because the mean of its divisors is an integer number (990700721806).

Almost surely, 2^{1981401443611} is an apocalyptic number.

1981401443611 is a deficient number, since it is larger than the sum of its proper divisors (1).

1981401443611 is an equidigital number, since it uses as much as digits as its factorization.

1981401443611 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 82944, while the sum is 43.

The spelling of 1981401443611 in words is "one trillion, nine hundred eighty-one billion, four hundred one million, four hundred forty-three thousand, six hundred eleven".