11581521 has 16 divisors (see below), whose sum is σ = 17939328. Its totient is φ = 6508800.

The previous prime is 11581517. The next prime is 11581529. The reversal of 11581521 is 12518511.

11581521 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 11581521 - 2² = 11581517 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 11581491 and 11581500.

It is not an unprimeable number, because it can be changed into a prime (11581529) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3240 + ... + 5801.

It is an arithmetic number, because the mean of its divisors is an integer number (1121208).

Almost surely, 2^11581521 is an apocalyptic number.

It is an amenable number.

11581521 is a deficient number, since it is larger than the sum of its proper divisors (6357807).

11581521 is an equidigital number, since it uses as much as digits as its factorization.

11581521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9112.

The product of its digits is 400, while the sum is 24.

The square root of 11581521 is about 3403.1633813263. The cubic root of 11581521 is about 226.2499714091.

It can be divided in two parts, 115815 and 21, that multiplied together give a triangular number (2432115 = T₂₂₀₅).

The spelling of 11581521 in words is "eleven million, five hundred eighty-one thousand, five hundred twenty-one".