11943821 has 2 divisors, whose sum is σ = 11943822. Its totient is φ = 11943820.

The previous prime is 11943817. The next prime is 11943823. The reversal of 11943821 is 12834911.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7761796 + 4182025 = 2786^2 + 2045^2 .

It is an emirp because it is prime and its reverse (12834911) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 11943821 - 2² = 11943817 is a prime.

Together with 11943823, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11943823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5971910 + 5971911.

It is an arithmetic number, because the mean of its divisors is an integer number (5971911).

Almost surely, 2^11943821 is an apocalyptic number.

It is an amenable number.

11943821 is a deficient number, since it is larger than the sum of its proper divisors (1).

11943821 is an equidigital number, since it uses as much as digits as its factorization.

11943821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1728, while the sum is 29.

The square root of 11943821 is about 3455.9833622285. The cubic root of 11943821 is about 228.5850178491.

The spelling of 11943821 in words is "eleven million, nine hundred forty-three thousand, eight hundred twenty-one".