11806573581 has 16 divisors (see below), whose sum is σ = 19081331520. Its totient is φ = 7155498960.

The previous prime is 11806573577. The next prime is 11806573643. The reversal of 11806573581 is 18537560811.

11806573581 is a `hidden beast` number, since 1 + 1 + 8 + 0 + 65 + 7 + 3 + 581 = 666.

11806573581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 11806573581 - 2² = 11806573577 is a prime.

It is a super-2 number, since 2×11806573581² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11806573561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19876090 + ... + 19876683.

It is an arithmetic number, because the mean of its divisors is an integer number (1192583220).

Almost surely, 2^11806573581 is an apocalyptic number.

11806573581 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

11806573581 is a deficient number, since it is larger than the sum of its proper divisors (7274757939).

11806573581 is a wasteful number, since it uses less digits than its factorization.

11806573581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39752793 (or 39752787 counting only the distinct ones).

The product of its (nonzero) digits is 201600, while the sum is 45.

The spelling of 11806573581 in words is "eleven billion, eight hundred six million, five hundred seventy-three thousand, five hundred eighty-one".