11021221209991 has 2 divisors, whose sum is σ = 11021221209992. Its totient is φ = 11021221209990.

The previous prime is 11021221209961. The next prime is 11021221210031. The reversal of 11021221209991 is 19990212212011.

11021221209991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an a-pointer prime, because the next prime (11021221210031) can be obtained adding 11021221209991 to its sum of digits (40).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 11021221209991 - 2²⁹ = 11020684339079 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11021221209961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5510610604995 + 5510610604996.

It is an arithmetic number, because the mean of its divisors is an integer number (5510610604996).

Almost surely, 2^{11021221209991} is an apocalyptic number.

11021221209991 is a deficient number, since it is larger than the sum of its proper divisors (1).

11021221209991 is an equidigital number, since it uses as much as digits as its factorization.

11021221209991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 40.

The spelling of 11021221209991 in words is "eleven trillion, twenty-one billion, two hundred twenty-one million, two hundred nine thousand, nine hundred ninety-one".