123145661 has 2 divisors, whose sum is σ = 123145662. Its totient is φ = 123145660.

The previous prime is 123145643. The next prime is 123145681. The reversal of 123145661 is 166541321.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 96157636 + 26988025 = 9806^2 + 5195^2 .

It is a cyclic number.

It is not a de Polignac number, because 123145661 - 2⁶ = 123145597 is a prime.

It is a Sophie Germain prime.

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 (123145621) 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, 61572830 + 61572831.

It is an arithmetic number, because the mean of its divisors is an integer number (61572831).

Almost surely, 2^123145661 is an apocalyptic number.

It is an amenable number.

123145661 is a deficient number, since it is larger than the sum of its proper divisors (1).

123145661 is an equidigital number, since it uses as much as digits as its factorization.

123145661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4320, while the sum is 29.

The square root of 123145661 is about 11097.1014684016. The cubic root of 123145661 is about 497.5152201938.

Adding to 123145661 its reverse (166541321), we get a palindrome (289686982).

The spelling of 123145661 in words is "one hundred twenty-three million, one hundred forty-five thousand, six hundred sixty-one".