11781391 has 8 divisors (see below), whose sum is σ = 12779424. Its totient is φ = 10817280.

The previous prime is 11781389. The next prime is 11781421. The reversal of 11781391 is 19318711.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 11781391 - 2¹ = 11781389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11781361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7755 + ... + 9148.

It is an arithmetic number, because the mean of its divisors is an integer number (1597428).

Almost surely, 2^11781391 is an apocalyptic number.

11781391 is a deficient number, since it is larger than the sum of its proper divisors (998033).

11781391 is a wasteful number, since it uses less digits than its factorization.

11781391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16961.

The product of its digits is 1512, while the sum is 31.

The square root of 11781391 is about 3432.4030940436. The cubic root of 11781391 is about 227.5440706797.

The spelling of 11781391 in words is "eleven million, seven hundred eighty-one thousand, three hundred ninety-one".