11563781 has 2 divisors, whose sum is σ = 11563782. Its totient is φ = 11563780.

The previous prime is 11563771. The next prime is 11563789. The reversal of 11563781 is 18736511.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11282881 + 280900 = 3359^2 + 530^2 .

It is a cyclic number.

It is not a de Polignac number, because 11563781 - 2²² = 7369477 is a prime.

It is a super-2 number, since 2×11563781² = 267442062031922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11563789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5781890 + 5781891.

It is an arithmetic number, because the mean of its divisors is an integer number (5781891).

Almost surely, 2^11563781 is an apocalyptic number.

It is an amenable number.

11563781 is a deficient number, since it is larger than the sum of its proper divisors (1).

11563781 is an equidigital number, since it uses as much as digits as its factorization.

11563781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5040, while the sum is 32.

The square root of 11563781 is about 3400.5559839532. Note that the first 3 decimals coincide. The cubic root of 11563781 is about 226.1343928780.

The spelling of 11563781 in words is "eleven million, five hundred sixty-three thousand, seven hundred eighty-one".