11821111 has 4 divisors (see below), whose sum is σ = 12072672. Its totient is φ = 11569552.

The previous prime is 11821081. The next prime is 11821123. The reversal of 11821111 is 11112811.

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 11821111 - 2¹³ = 11812919 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 (11821151) 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, 125710 + ... + 125803.

It is an arithmetic number, because the mean of its divisors is an integer number (3018168).

Almost surely, 2^11821111 is an apocalyptic number.

11821111 is a deficient number, since it is larger than the sum of its proper divisors (251561).

11821111 is an equidigital number, since it uses as much as digits as its factorization.

11821111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 251560.

The product of its digits is 16, while the sum is 16.

The square root of 11821111 is about 3438.1842591694. The cubic root of 11821111 is about 227.7994992747.

Adding to 11821111 its reverse (11112811), we get a palindrome (22933922).

It can be divided in two parts, 11821 and 111, that multiplied together give a palindrome (1312131).

The spelling of 11821111 in words is "eleven million, eight hundred twenty-one thousand, one hundred eleven".