13331561 has 8 divisors (see below), whose sum is σ = 13857480. Its totient is φ = 12810112.

The previous prime is 13331557. The next prime is 13331569. The reversal of 13331561 is 16513331.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 118336 + 13213225 = 344^2 + 3635^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 13331561 - 2² = 13331557 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13331569) 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 7 ways as a sum of consecutive naturals, for example, 5771 + ... + 7743.

It is an arithmetic number, because the mean of its divisors is an integer number (1732185).

Almost surely, 2^13331561 is an apocalyptic number.

It is an amenable number.

13331561 is a deficient number, since it is larger than the sum of its proper divisors (525919).

13331561 is a wasteful number, since it uses less digits than its factorization.

13331561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2235.

The product of its digits is 810, while the sum is 23.

The square root of 13331561 is about 3651.2410218993. The cubic root of 13331561 is about 237.1157131662.

Adding to 13331561 its reverse (16513331), we get a palindrome (29844892).

The spelling of 13331561 in words is "thirteen million, three hundred thirty-one thousand, five hundred sixty-one".