11820553 has 4 divisors (see below), whose sum is σ = 11829888. Its totient is φ = 11811220.

The previous prime is 11820539. The next prime is 11820563. The reversal of 11820553 is 35502811.

It is a happy number.

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 a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 35502811 = 19 ⋅1868569.

It is a cyclic number.

It is not a de Polignac number, because 11820553 - 2⁵ = 11820521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11820563) 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, 2401 + ... + 5422.

It is an arithmetic number, because the mean of its divisors is an integer number (2957472).

Almost surely, 2^11820553 is an apocalyptic number.

It is an amenable number.

11820553 is a deficient number, since it is larger than the sum of its proper divisors (9335).

11820553 is an equidigital number, since it uses as much as digits as its factorization.

11820553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9334.

The product of its (nonzero) digits is 1200, while the sum is 25.

The square root of 11820553 is about 3438.1031107284. The cubic root of 11820553 is about 227.7959148930.

The spelling of 11820553 in words is "eleven million, eight hundred twenty thousand, five hundred fifty-three".