11993581 has 2 divisors, whose sum is σ = 11993582. Its totient is φ = 11993580.

The previous prime is 11993563. The next prime is 11993591. The reversal of 11993581 is 18539911.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11964681 + 28900 = 3459^2 + 170^2 .

It is a cyclic number.

It is not a de Polignac number, because 11993581 - 2⁵ = 11993549 is a prime.

It is a super-2 number, since 2×11993581² = 287691970407122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 11993581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11993521) 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 as a sum of consecutive naturals, namely, 5996790 + 5996791.

It is an arithmetic number, because the mean of its divisors is an integer number (5996791).

Almost surely, 2^11993581 is an apocalyptic number.

It is an amenable number.

11993581 is a deficient number, since it is larger than the sum of its proper divisors (1).

11993581 is an equidigital number, since it uses as much as digits as its factorization.

11993581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9720, while the sum is 37.

The square root of 11993581 is about 3463.1749883597. The cubic root of 11993581 is about 228.9020194480.

The spelling of 11993581 in words is "eleven million, nine hundred ninety-three thousand, five hundred eighty-one".