1205117789 has 2 divisors, whose sum is σ = 1205117790. Its totient is φ = 1205117788.

The previous prime is 1205117783. The next prime is 1205117791. The reversal of 1205117789 is 9877115021.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 678185764 + 526932025 = 26042^2 + 22955^2 .

It is a cyclic number.

It is not a de Polignac number, because 1205117789 - 2²⁰ = 1204069213 is a prime.

Together with 1205117791, 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 (1205117783) 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, 602558894 + 602558895.

It is an arithmetic number, because the mean of its divisors is an integer number (602558895).

Almost surely, 2^1205117789 is an apocalyptic number.

It is an amenable number.

1205117789 is a deficient number, since it is larger than the sum of its proper divisors (1).

1205117789 is an equidigital number, since it uses as much as digits as its factorization.

1205117789 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 35280, while the sum is 41.

The square root of 1205117789 is about 34714.8064808087. The cubic root of 1205117789 is about 1064.1671106383.

The spelling of 1205117789 in words is "one billion, two hundred five million, one hundred seventeen thousand, seven hundred eighty-nine".