13115521 has 4 divisors (see below), whose sum is σ = 13135572. Its totient is φ = 13095472.

The previous prime is 13115513. The next prime is 13115527. The reversal of 13115521 is 12551131.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9641025 + 3474496 = 3105^2 + 1864^2 .

It is a cyclic number.

It is not a de Polignac number, because 13115521 - 2³ = 13115513 is a prime.

It is a super-2 number, since 2×13115521² = 344033782202882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13115527) 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, 9010 + ... + 10363.

It is an arithmetic number, because the mean of its divisors is an integer number (3283893).

Almost surely, 2^13115521 is an apocalyptic number.

It is an amenable number.

13115521 is a deficient number, since it is larger than the sum of its proper divisors (20051).

13115521 is an equidigital number, since it uses as much as digits as its factorization.

13115521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20050.

The product of its digits is 150, while the sum is 19.

The square root of 13115521 is about 3621.5357239713. The cubic root of 13115521 is about 235.8278992811.

Adding to 13115521 its reverse (12551131), we get a palindrome (25666652).

The spelling of 13115521 in words is "thirteen million, one hundred fifteen thousand, five hundred twenty-one".