1001001010991 has 2 divisors, whose sum is σ = 1001001010992. Its totient is φ = 1001001010990.

The previous prime is 1001001010943. The next prime is 1001001011009. The reversal of 1001001010991 is 1990101001001.

It is a happy number.

1001001010991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is an emirp because it is prime and its reverse (1990101001001) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1001001010991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1001001010591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 500500505495 + 500500505496.

It is an arithmetic number, because the mean of its divisors is an integer number (500500505496).

Almost surely, 2^{1001001010991} is an apocalyptic number.

1001001010991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1001001010991 is an equidigital number, since it uses as much as digits as its factorization.

1001001010991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 81, while the sum is 23.

Adding to 1001001010991 its reverse (1990101001001), we get a palindrome (2991102011992).

The spelling of 1001001010991 in words is "one trillion, one billion, one million, ten thousand, nine hundred ninety-one".