11931989 has 2 divisors, whose sum is σ = 11931990. Its totient is φ = 11931988.

The previous prime is 11931967. The next prime is 11931991. The reversal of 11931989 is 98913911.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7236100 + 4695889 = 2690^2 + 2167^2 .

It is a cyclic number.

It is not a de Polignac number, because 11931989 - 2¹² = 11927893 is a prime.

It is a super-2 number, since 2×11931989² = 284744722992242, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 11931991, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11931919) 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, 5965994 + 5965995.

It is an arithmetic number, because the mean of its divisors is an integer number (5965995).

Almost surely, 2^11931989 is an apocalyptic number.

It is an amenable number.

11931989 is a deficient number, since it is larger than the sum of its proper divisors (1).

11931989 is an equidigital number, since it uses as much as digits as its factorization.

11931989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17496, while the sum is 41.

The square root of 11931989 is about 3454.2711242750. The cubic root of 11931989 is about 228.5095112608.

The spelling of 11931989 in words is "eleven million, nine hundred thirty-one thousand, nine hundred eighty-nine".