11556381 has 4 divisors (see below), whose sum is σ = 15408512. Its totient is φ = 7704252.

The previous prime is 11556359. The next prime is 11556409. The reversal of 11556381 is 18365511.

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 11556381 - 2⁶ = 11556317 is a prime.

It is a super-2 number, since 2×11556381² = 267099883634322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11556331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1926061 + ... + 1926066.

It is an arithmetic number, because the mean of its divisors is an integer number (3852128).

Almost surely, 2^11556381 is an apocalyptic number.

It is an amenable number.

11556381 is a deficient number, since it is larger than the sum of its proper divisors (3852131).

11556381 is an equidigital number, since it uses as much as digits as its factorization.

11556381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3852130.

The product of its digits is 3600, while the sum is 30.

The square root of 11556381 is about 3399.4677524577. The cubic root of 11556381 is about 226.0861459253.

The spelling of 11556381 in words is "eleven million, five hundred fifty-six thousand, three hundred eighty-one".