1981155671041 has 2 divisors, whose sum is σ = 1981155671042. Its totient is φ = 1981155671040.

The previous prime is 1981155671029. The next prime is 1981155671059. The reversal of 1981155671041 is 1401765511891.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1523508833025 + 457646838016 = 1234305^2 + 676496^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1981155671041 is a prime.

It is not a weakly prime, because it can be changed into another prime (1981155671021) by changing a digit.

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 as a sum of consecutive naturals, namely, 990577835520 + 990577835521.

It is an arithmetic number, because the mean of its divisors is an integer number (990577835521).

Almost surely, 2^{1981155671041} is an apocalyptic number.

It is an amenable number.

1981155671041 is a deficient number, since it is larger than the sum of its proper divisors (1).

1981155671041 is an equidigital number, since it uses as much as digits as its factorization.

1981155671041 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 302400, while the sum is 49.

The spelling of 1981155671041 in words is "one trillion, nine hundred eighty-one billion, one hundred fifty-five million, six hundred seventy-one thousand, forty-one".