1091711255221 has 2 divisors, whose sum is σ = 1091711255222. Its totient is φ = 1091711255220.

The previous prime is 1091711255191. The next prime is 1091711255231. The reversal of 1091711255221 is 1225521171901.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 681136596100 + 410574659121 = 825310^2 + 640761^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1091711255221 is a prime.

It is a super-2 number, since 2×1091711255221² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1091711255231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 545855627610 + 545855627611.

It is an arithmetic number, because the mean of its divisors is an integer number (545855627611).

Almost surely, 2^{1091711255221} is an apocalyptic number.

It is an amenable number.

1091711255221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1091711255221 is an equidigital number, since it uses as much as digits as its factorization.

1091711255221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12600, while the sum is 37.

The spelling of 1091711255221 in words is "one trillion, ninety-one billion, seven hundred eleven million, two hundred fifty-five thousand, two hundred twenty-one".