1118371781 has 2 divisors, whose sum is σ = 1118371782. Its totient is φ = 1118371780.

The previous prime is 1118371763. The next prime is 1118371783. The reversal of 1118371781 is 1871738111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1069944100 + 48427681 = 32710^2 + 6959^2 .

It is a cyclic number.

It is not a de Polignac number, because 1118371781 - 2³⁰ = 44629957 is a prime.

It is a super-2 number, since 2×1118371781² = 2501510881074223922, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 1118371783, 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 (1118371783) 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, 559185890 + 559185891.

It is an arithmetic number, because the mean of its divisors is an integer number (559185891).

Almost surely, 2^1118371781 is an apocalyptic number.

It is an amenable number.

1118371781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1118371781 is an equidigital number, since it uses as much as digits as its factorization.

1118371781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9408, while the sum is 38.

The square root of 1118371781 is about 33442.0660396453. The cubic root of 1118371781 is about 1037.9953312135.

The spelling of 1118371781 in words is "one billion, one hundred eighteen million, three hundred seventy-one thousand, seven hundred eighty-one".