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11391 has 4 divisors (see below), whose sum is σ = 15192. Its totient is φ = 7592.

The previous prime is 11383. The next prime is 11393. The reversal of 11391 is 19311.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 11391 - 23 = 11383 is a prime.

It is a D-number.

11391 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 11391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11393) 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, 1896 + ... + 1901.

It is an arithmetic number, because the mean of its divisors is an integer number (3798).

211391 is an apocalyptic number.

11391 is the 68-th centered pentagonal number.

11391 is a deficient number, since it is larger than the sum of its proper divisors (3801).

11391 is an equidigital number, since it uses as much as digits as its factorization.

11391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3800.

The product of its digits is 27, while the sum is 15.

The square root of 11391 is about 106.7286278371. The cubic root of 11391 is about 22.5002469109.

The spelling of 11391 in words is "eleven thousand, three hundred ninety-one".

Divisors: 1 3 3797 11391