11551555 has 4 divisors (see below), whose sum is σ = 13861872. Its totient is φ = 9241240.

The previous prime is 11551531. The next prime is 11551559. The reversal of 11551555 is 55515511.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 55515511 = 19 ⋅2921869.

It is not a de Polignac number, because 11551555 - 2⁷ = 11551427 is a prime.

It is a nude number because it is divisible by every one of its digits.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11551559) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1155151 + ... + 1155160.

It is an arithmetic number, because the mean of its divisors is an integer number (3465468).

Almost surely, 2^11551555 is an apocalyptic number.

11551555 is a deficient number, since it is larger than the sum of its proper divisors (2310317).

11551555 is an equidigital number, since it uses as much as digits as its factorization.

11551555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2310316.

The product of its digits is 3125, while the sum is 28.

The square root of 11551555 is about 3398.7578613370. The cubic root of 11551555 is about 226.0546699913.

It can be divided in two parts, 1155155 and 5, that multiplied together give a palindrome (5775775).

The spelling of 11551555 in words is "eleven million, five hundred fifty-one thousand, five hundred fifty-five".