11156540491 has 2 divisors, whose sum is σ = 11156540492. Its totient is φ = 11156540490.

The previous prime is 11156540489. The next prime is 11156540623. The reversal of 11156540491 is 19404565111.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 11156540491 - 2¹ = 11156540489 is a prime.

Together with 11156540489, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 11156540491.

It is not a weakly prime, because it can be changed into another prime (11156540401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5578270245 + 5578270246.

It is an arithmetic number, because the mean of its divisors is an integer number (5578270246).

Almost surely, 2^11156540491 is an apocalyptic number.

11156540491 is a deficient number, since it is larger than the sum of its proper divisors (1).

11156540491 is an equidigital number, since it uses as much as digits as its factorization.

11156540491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21600, while the sum is 37.

The spelling of 11156540491 in words is "eleven billion, one hundred fifty-six million, five hundred forty thousand, four hundred ninety-one".