11566987909 has 2 divisors, whose sum is σ = 11566987910. Its totient is φ = 11566987908.

The previous prime is 11566987889. The next prime is 11566987931. The reversal of 11566987909 is 90978966511.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11104522884 + 462465025 = 105378^2 + 21505^2 .

It is a cyclic number.

It is not a de Polignac number, because 11566987909 - 2⁵ = 11566987877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11566987709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5783493954 + 5783493955.

It is an arithmetic number, because the mean of its divisors is an integer number (5783493955).

Almost surely, 2^11566987909 is an apocalyptic number.

It is an amenable number.

11566987909 is a deficient number, since it is larger than the sum of its proper divisors (1).

11566987909 is an equidigital number, since it uses as much as digits as its factorization.

11566987909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7348320, while the sum is 61.

The spelling of 11566987909 in words is "eleven billion, five hundred sixty-six million, nine hundred eighty-seven thousand, nine hundred nine".