11723981 has 2 divisors, whose sum is σ = 11723982. Its totient is φ = 11723980.

The previous prime is 11723977. The next prime is 11723989. The reversal of 11723981 is 18932711.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6295081 + 5428900 = 2509^2 + 2330^2 .

It is a cyclic number.

It is not a de Polignac number, because 11723981 - 2² = 11723977 is a prime.

It is a super-2 number, since 2×11723981² = 274903460976722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11723989) 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 as a sum of consecutive naturals, namely, 5861990 + 5861991.

It is an arithmetic number, because the mean of its divisors is an integer number (5861991).

Almost surely, 2^11723981 is an apocalyptic number.

It is an amenable number.

11723981 is a deficient number, since it is larger than the sum of its proper divisors (1).

11723981 is an equidigital number, since it uses as much as digits as its factorization.

11723981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 32.

The square root of 11723981 is about 3424.0299356168. The cubic root of 11723981 is about 227.1738659043.

The spelling of 11723981 in words is "eleven million, seven hundred twenty-three thousand, nine hundred eighty-one".