1165123005581 has 2 divisors, whose sum is σ = 1165123005582. Its totient is φ = 1165123005580.

The previous prime is 1165123005577. The next prime is 1165123005583. The reversal of 1165123005581 is 1855003215611.

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., 1082328122500 + 82794883081 = 1040350^2 + 287741^2 .

It is a cyclic number.

It is not a de Polignac number, because 1165123005581 - 2² = 1165123005577 is a prime.

It is a super-2 number, since 2×1165123005581² (a number of 25 digits) contains 22 as substring.

Together with 1165123005583, 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 (1165123005583) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 582561502790 + 582561502791.

It is an arithmetic number, because the mean of its divisors is an integer number (582561502791).

Almost surely, 2^{1165123005581} is an apocalyptic number.

It is an amenable number.

1165123005581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1165123005581 is an equidigital number, since it uses as much as digits as its factorization.

1165123005581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36000, while the sum is 38.

The spelling of 1165123005581 in words is "one trillion, one hundred sixty-five billion, one hundred twenty-three million, five thousand, five hundred eighty-one".