11775581 has 4 divisors (see below), whose sum is σ = 11789472. Its totient is φ = 11761692.

The previous prime is 11775571. The next prime is 11775601. The reversal of 11775581 is 18557711.

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: 18557711 = 23 ⋅806857.

It is a cyclic number.

It is not a de Polignac number, because 11775581 - 2¹⁴ = 11759197 is a prime.

It is a super-2 number, since 2×11775581² = 277328615775122, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11775541) 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, 5585 + ... + 7398.

It is an arithmetic number, because the mean of its divisors is an integer number (2947368).

Almost surely, 2^11775581 is an apocalyptic number.

It is an amenable number.

11775581 is a deficient number, since it is larger than the sum of its proper divisors (13891).

11775581 is an equidigital number, since it uses as much as digits as its factorization.

11775581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13890.

The product of its digits is 9800, while the sum is 35.

The square root of 11775581 is about 3431.5566438571. The cubic root of 11775581 is about 227.5066600312.

The spelling of 11775581 in words is "eleven million, seven hundred seventy-five thousand, five hundred eighty-one".