11557991 has 2 divisors, whose sum is σ = 11557992. Its totient is φ = 11557990.

The previous prime is 11557981. The next prime is 11558021. The reversal of 11557991 is 19975511.

11557991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 11557991 - 2¹⁰ = 11556967 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11557951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5778995 + 5778996.

It is an arithmetic number, because the mean of its divisors is an integer number (5778996).

Almost surely, 2^11557991 is an apocalyptic number.

11557991 is a deficient number, since it is larger than the sum of its proper divisors (1).

11557991 is an equidigital number, since it uses as much as digits as its factorization.

11557991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14175, while the sum is 38.

The square root of 11557991 is about 3399.7045459863. The cubic root of 11557991 is about 226.0966446501.

The spelling of 11557991 in words is "eleven million, five hundred fifty-seven thousand, nine hundred ninety-one".