1168555721 has 2 divisors, whose sum is σ = 1168555722. Its totient is φ = 1168555720.

The previous prime is 1168555699. The next prime is 1168555723. The reversal of 1168555721 is 1275558611.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1088274121 + 80281600 = 32989^2 + 8960^2 .

It is an emirp because it is prime and its reverse (1275558611) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1168555721 - 2¹⁰ = 1168554697 is a prime.

Together with 1168555723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1168555723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 584277860 + 584277861.

It is an arithmetic number, because the mean of its divisors is an integer number (584277861).

Almost surely, 2^1168555721 is an apocalyptic number.

It is an amenable number.

1168555721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1168555721 is an equidigital number, since it uses as much as digits as its factorization.

1168555721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 84000, while the sum is 41.

The square root of 1168555721 is about 34184.1442923470. The cubic root of 1168555721 is about 1053.2944811441.

The spelling of 1168555721 in words is "one billion, one hundred sixty-eight million, five hundred fifty-five thousand, seven hundred twenty-one".