11011211010991 has 2 divisors, whose sum is σ = 11011211010992. Its totient is φ = 11011211010990.

The previous prime is 11011211010889. The next prime is 11011211011007. The reversal of 11011211010991 is 19901011211011.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 11011211010991 - 2²¹ = 11011208913839 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11011221010991) 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, 5505605505495 + 5505605505496.

It is an arithmetic number, because the mean of its divisors is an integer number (5505605505496).

Almost surely, 2^{11011211010991} is an apocalyptic number.

11011211010991 is a deficient number, since it is larger than the sum of its proper divisors (1).

11011211010991 is an equidigital number, since it uses as much as digits as its factorization.

11011211010991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 162, while the sum is 28.

It can be divided in two parts, 1101121 and 1010991, that added together give a palindrome (2112112).

The spelling of 11011211010991 in words is "eleven trillion, eleven billion, two hundred eleven million, ten thousand, nine hundred ninety-one".