13128961 has 4 divisors (see below), whose sum is σ = 13136212. Its totient is φ = 13121712.

The previous prime is 13128949. The next prime is 13128971. The reversal of 13128961 is 16982131.

13128961 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 10439361 + 2689600 = 3231^2 + 1640^2 .

It is a cyclic number.

It is not a de Polignac number, because 13128961 - 2⁷ = 13128833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13128901) 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, 1651 + ... + 5383.

It is an arithmetic number, because the mean of its divisors is an integer number (3284053).

Almost surely, 2^13128961 is an apocalyptic number.

It is an amenable number.

13128961 is a deficient number, since it is larger than the sum of its proper divisors (7251).

13128961 is an equidigital number, since it uses as much as digits as its factorization.

13128961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7250.

The product of its digits is 2592, while the sum is 31.

The square root of 13128961 is about 3623.3908152447. The cubic root of 13128961 is about 235.9084258810.

It can be divided in two parts, 131 and 28961, that added together give a palindrome (29092).

The spelling of 13128961 in words is "thirteen million, one hundred twenty-eight thousand, nine hundred sixty-one".