11722561 has 4 divisors (see below), whose sum is σ = 11756500. Its totient is φ = 11688624.

The previous prime is 11722519. The next prime is 11722589. The reversal of 11722561 is 16522711.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16522711 = 173 ⋅95507.

It can be written as a sum of positive squares in 2 ways, for example, as 10523536 + 1199025 = 3244^2 + 1095^2 .

It is a cyclic number.

It is not a de Polignac number, because 11722561 - 2⁹ = 11722049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11722511) 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, 16446 + ... + 17143.

It is an arithmetic number, because the mean of its divisors is an integer number (2939125).

Almost surely, 2^11722561 is an apocalyptic number.

It is an amenable number.

11722561 is a deficient number, since it is larger than the sum of its proper divisors (33939).

11722561 is an equidigital number, since it uses as much as digits as its factorization.

11722561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33938.

The product of its digits is 840, while the sum is 25.

The square root of 11722561 is about 3423.8225713375. The cubic root of 11722561 is about 227.1646938232.

The spelling of 11722561 in words is "eleven million, seven hundred twenty-two thousand, five hundred sixty-one".