11381 has 4 divisors (see below), whose sum is σ = 12000. Its totient is φ = 10764.

The previous prime is 11369. The next prime is 11383. The reversal of 11381 is 18311.

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 a cyclic number.

It is not a de Polignac number, because 11381 - 2⁶ = 11317 is a prime.

It is a super-2 number, since 2×11381² = 259054322, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11383) 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, 281 + ... + 318.

It is an arithmetic number, because the mean of its divisors is an integer number (3000).

2¹¹³⁸¹ is an apocalyptic number.

It is an amenable number.

11381 is a deficient number, since it is larger than the sum of its proper divisors (619).

11381 is an equidigital number, since it uses as much as digits as its factorization.

11381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 618.

The product of its digits is 24, while the sum is 14.

The square root of 11381 is about 106.6817697641. The cubic root of 11381 is about 22.4936607656.

Adding to 11381 its reverse (18311), we get a palindrome (29692).

The spelling of 11381 in words is "eleven thousand, three hundred eighty-one".