11718821 has 2 divisors, whose sum is σ = 11718822. Its totient is φ = 11718820.

The previous prime is 11718809. The next prime is 11718823. The reversal of 11718821 is 12881711.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11296321 + 422500 = 3361^2 + 650^2 .

It is an emirp because it is prime and its reverse (12881711) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 11718821 - 2¹⁴ = 11702437 is a prime.

Together with 11718823, 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 (11718823) 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 as a sum of consecutive naturals, namely, 5859410 + 5859411.

It is an arithmetic number, because the mean of its divisors is an integer number (5859411).

Almost surely, 2^11718821 is an apocalyptic number.

It is an amenable number.

11718821 is a deficient number, since it is larger than the sum of its proper divisors (1).

11718821 is an equidigital number, since it uses as much as digits as its factorization.

11718821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 896, while the sum is 29.

The square root of 11718821 is about 3423.2763546053. The cubic root of 11718821 is about 227.1405328251.

The spelling of 11718821 in words is "eleven million, seven hundred eighteen thousand, eight hundred twenty-one".