11557681 has 4 divisors (see below), whose sum is σ = 12166000. Its totient is φ = 10949364.

The previous prime is 11557673. The next prime is 11557697. The reversal of 11557681 is 18675511.

11557681 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18675511 = 149 ⋅125339.

It is a cyclic number.

It is not a de Polignac number, because 11557681 - 2³ = 11557673 is a prime.

It is a super-2 number, since 2×11557681² = 267159980195522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11557081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 304131 + ... + 304168.

It is an arithmetic number, because the mean of its divisors is an integer number (3041500).

Almost surely, 2^11557681 is an apocalyptic number.

It is an amenable number.

11557681 is a deficient number, since it is larger than the sum of its proper divisors (608319).

11557681 is an equidigital number, since it uses as much as digits as its factorization.

11557681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 608318.

The product of its digits is 8400, while the sum is 34.

The square root of 11557681 is about 3399.6589534834. The cubic root of 11557681 is about 226.0946232323.

It can be divided in two parts, 1155 and 7681, that added together give a square (8836 = 94²).

The spelling of 11557681 in words is "eleven million, five hundred fifty-seven thousand, six hundred eighty-one".