11821811 has 4 divisors (see below), whose sum is σ = 11907000. Its totient is φ = 11736624.

The previous prime is 11821787. The next prime is 11821841. The reversal of 11821811 is 11812811.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11821811 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11821841) 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 3 ways as a sum of consecutive naturals, for example, 42386 + ... + 42663.

It is an arithmetic number, because the mean of its divisors is an integer number (2976750).

Almost surely, 2^11821811 is an apocalyptic number.

11821811 is a deficient number, since it is larger than the sum of its proper divisors (85189).

11821811 is an equidigital number, since it uses as much as digits as its factorization.

11821811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85188.

The product of its digits is 128, while the sum is 23.

The square root of 11821811 is about 3438.2860555806. The cubic root of 11821811 is about 227.8039956514.

The spelling of 11821811 in words is "eleven million, eight hundred twenty-one thousand, eight hundred eleven".