11011211211991 has 2 divisors, whose sum is σ = 11011211211992. Its totient is φ = 11011211211990.

The previous prime is 11011211211943. The next prime is 11011211212003. The reversal of 11011211211991 is 19911211211011.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 11011211211991 - 2¹³ = 11011211203799 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11011211911991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5505605605995 + 5505605605996.

It is an arithmetic number, because the mean of its divisors is an integer number (5505605605996).

Almost surely, 2^{11011211211991} is an apocalyptic number.

11011211211991 is a deficient number, since it is larger than the sum of its proper divisors (1).

11011211211991 is an equidigital number, since it uses as much as digits as its factorization.

11011211211991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324, while the sum is 31.

The spelling of 11011211211991 in words is "eleven trillion, eleven billion, two hundred eleven million, two hundred eleven thousand, nine hundred ninety-one".