11723561 has 4 divisors (see below), whose sum is σ = 12040452. Its totient is φ = 11406672.

The previous prime is 11723527. The next prime is 11723573. The reversal of 11723561 is 16532711.

11723561 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 an emirpimes, since its reverse is a distinct semiprime: 16532711 = 13 ⋅1271747.

It can be written as a sum of positive squares in 2 ways, for example, as 4541161 + 7182400 = 2131^2 + 2680^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11723561 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 11723561.

It is not an unprimeable number, because it can be changed into a prime (11723161) 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, 158390 + ... + 158463.

It is an arithmetic number, because the mean of its divisors is an integer number (3010113).

Almost surely, 2^11723561 is an apocalyptic number.

It is an amenable number.

11723561 is a deficient number, since it is larger than the sum of its proper divisors (316891).

11723561 is an equidigital number, since it uses as much as digits as its factorization.

11723561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 316890.

The product of its digits is 1260, while the sum is 26.

The square root of 11723561 is about 3423.9686038280. The cubic root of 11723561 is about 227.1711531124.

The spelling of 11723561 in words is "eleven million, seven hundred twenty-three thousand, five hundred sixty-one".