13091561 has 4 divisors (see below), whose sum is σ = 14961792. Its totient is φ = 11221332.

The previous prime is 13091539. The next prime is 13091563. The reversal of 13091561 is 16519031.

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 an emirpimes, since its reverse is a distinct semiprime: 16519031 = 1153 ⋅14327.

It is a cyclic number.

It is not a de Polignac number, because 13091561 - 2⁶ = 13091497 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 13091561.

It is not an unprimeable number, because it can be changed into a prime (13091563) 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 3 ways as a sum of consecutive naturals, for example, 935105 + ... + 935118.

It is an arithmetic number, because the mean of its divisors is an integer number (3740448).

Almost surely, 2^13091561 is an apocalyptic number.

It is an amenable number.

13091561 is a deficient number, since it is larger than the sum of its proper divisors (1870231).

13091561 is an equidigital number, since it uses as much as digits as its factorization.

13091561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1870230.

The product of its (nonzero) digits is 810, while the sum is 26.

The square root of 13091561 is about 3618.2262228888. The cubic root of 13091561 is about 235.6842048806.

The spelling of 13091561 in words is "thirteen million, ninety-one thousand, five hundred sixty-one".