11641561 has 4 divisors (see below), whose sum is σ = 11648932. Its totient is φ = 11634192.

The previous prime is 11641559. The next prime is 11641579. The reversal of 11641561 is 16514611.

11641561 is digitally balanced in base 2, 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 8088336 + 3553225 = 2844^2 + 1885^2 .

It is a cyclic number.

It is not a de Polignac number, because 11641561 - 2¹ = 11641559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11641501) 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, 246 + ... + 4831.

It is an arithmetic number, because the mean of its divisors is an integer number (2912233).

Almost surely, 2^11641561 is an apocalyptic number.

It is an amenable number.

11641561 is a deficient number, since it is larger than the sum of its proper divisors (7371).

11641561 is an equidigital number, since it uses as much as digits as its factorization.

11641561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7370.

The product of its digits is 720, while the sum is 25.

The square root of 11641561 is about 3411.9731827786. The cubic root of 11641561 is about 226.6402667735.

The spelling of 11641561 in words is "eleven million, six hundred forty-one thousand, five hundred sixty-one".