11511887221 has 2 divisors, whose sum is σ = 11511887222. Its totient is φ = 11511887220.

The previous prime is 11511887197. The next prime is 11511887227. The reversal of 11511887221 is 12278811511.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9334264996 + 2177622225 = 96614^2 + 46665^2 .

It is an emirp because it is prime and its reverse (12278811511) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 11511887221 - 2⁹ = 11511886709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11511887227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5755943610 + 5755943611.

It is an arithmetic number, because the mean of its divisors is an integer number (5755943611).

Almost surely, 2^11511887221 is an apocalyptic number.

It is an amenable number.

11511887221 is a deficient number, since it is larger than the sum of its proper divisors (1).

11511887221 is an equidigital number, since it uses as much as digits as its factorization.

11511887221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8960, while the sum is 37.

The spelling of 11511887221 in words is "eleven billion, five hundred eleven million, eight hundred eighty-seven thousand, two hundred twenty-one".