11821859 has 4 divisors (see below), whose sum is σ = 13510704. Its totient is φ = 10133016.

The previous prime is 11821853. The next prime is 11821871. The reversal of 11821859 is 95812811.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 95812811 = 149 ⋅643039.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11821859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11821853) 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, 844412 + ... + 844425.

It is an arithmetic number, because the mean of its divisors is an integer number (3377676).

Almost surely, 2^11821859 is an apocalyptic number.

11821859 is a deficient number, since it is larger than the sum of its proper divisors (1688845).

11821859 is an equidigital number, since it uses as much as digits as its factorization.

11821859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1688844.

The product of its digits is 5760, while the sum is 35.

The square root of 11821859 is about 3438.2930357955. The cubic root of 11821859 is about 227.8043039678.

The spelling of 11821859 in words is "eleven million, eight hundred twenty-one thousand, eight hundred fifty-nine".