11131555 has 4 divisors (see below), whose sum is σ = 13357872. Its totient is φ = 8905240.

The previous prime is 11131553. The next prime is 11131559. The reversal of 11131555 is 55513111.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 55513111 = 61 ⋅910051.

It is not a de Polignac number, because 11131555 - 2¹ = 11131553 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11131553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1113151 + ... + 1113160.

It is an arithmetic number, because the mean of its divisors is an integer number (3339468).

Almost surely, 2^11131555 is an apocalyptic number.

11131555 is a deficient number, since it is larger than the sum of its proper divisors (2226317).

11131555 is an equidigital number, since it uses as much as digits as its factorization.

11131555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2226316.

The product of its digits is 375, while the sum is 22.

The square root of 11131555 is about 3336.3985073729. The cubic root of 11131555 is about 223.2810909709.

Adding to 11131555 its reverse (55513111), we get a palindrome (66644666).

The spelling of 11131555 in words is "eleven million, one hundred thirty-one thousand, five hundred fifty-five".