11527221781 has 2 divisors, whose sum is σ = 11527221782. Its totient is φ = 11527221780.

The previous prime is 11527221751. The next prime is 11527221787. The reversal of 11527221781 is 18712272511.

It is a happy number.

11527221781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9555062500 + 1972159281 = 97750^2 + 44409^2 .

It is a cyclic number.

It is not a de Polignac number, because 11527221781 - 2⁷ = 11527221653 is a prime.

It is a super-2 number, since 2×11527221781² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 11527221781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11527221787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5763610890 + 5763610891.

It is an arithmetic number, because the mean of its divisors is an integer number (5763610891).

Almost surely, 2^11527221781 is an apocalyptic number.

It is an amenable number.

11527221781 is a deficient number, since it is larger than the sum of its proper divisors (1).

11527221781 is an equidigital number, since it uses as much as digits as its factorization.

11527221781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15680, while the sum is 37.

The spelling of 11527221781 in words is "eleven billion, five hundred twenty-seven million, two hundred twenty-one thousand, seven hundred eighty-one".