13131561 has 8 divisors (see below), whose sum is σ = 17525664. Its totient is φ = 8745920.

The previous prime is 13131553. The next prime is 13131563. The reversal of 13131561 is 16513131.

13131561 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 13131561 - 2³ = 13131553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (13131563) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4225 + ... + 6641.

It is an arithmetic number, because the mean of its divisors is an integer number (2190708).

Almost surely, 2^13131561 is an apocalyptic number.

It is an amenable number.

13131561 is a deficient number, since it is larger than the sum of its proper divisors (4394103).

13131561 is a wasteful number, since it uses less digits than its factorization.

13131561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4231.

The product of its digits is 270, while the sum is 21.

The square root of 13131561 is about 3623.7495774405. The cubic root of 13131561 is about 235.9239975987.

Adding to 13131561 its reverse (16513131), we get a palindrome (29644692).

The spelling of 13131561 in words is "thirteen million, one hundred thirty-one thousand, five hundred sixty-one".