11543781 has 4 divisors (see below), whose sum is σ = 15391712. Its totient is φ = 7695852.

The previous prime is 11543767. The next prime is 11543789. The reversal of 11543781 is 18734511.

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.

It is not a de Polignac number, because 11543781 - 2⁹ = 11543269 is a prime.

It is a super-2 number, since 2×11543781² = 266517759551922, 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 (11543789) 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, 1923961 + ... + 1923966.

It is an arithmetic number, because the mean of its divisors is an integer number (3847928).

Almost surely, 2^11543781 is an apocalyptic number.

It is an amenable number.

11543781 is a deficient number, since it is larger than the sum of its proper divisors (3847931).

11543781 is an equidigital number, since it uses as much as digits as its factorization.

11543781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3847930.

The product of its digits is 3360, while the sum is 30.

The square root of 11543781 is about 3397.6140157469. The cubic root of 11543781 is about 226.0039482956.

The spelling of 11543781 in words is "eleven million, five hundred forty-three thousand, seven hundred eighty-one".