123235561 has 2 divisors, whose sum is σ = 123235562. Its totient is φ = 123235560.

The previous prime is 123235559. The next prime is 123235573. The reversal of 123235561 is 165532321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 121969936 + 1265625 = 11044^2 + 1125^2 .

It is an emirp because it is prime and its reverse (165532321) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 123235561 - 2¹ = 123235559 is a prime.

Together with 123235559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (123235061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61617780 + 61617781.

It is an arithmetic number, because the mean of its divisors is an integer number (61617781).

Almost surely, 2^123235561 is an apocalyptic number.

It is an amenable number.

123235561 is a deficient number, since it is larger than the sum of its proper divisors (1).

123235561 is an equidigital number, since it uses as much as digits as its factorization.

123235561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5400, while the sum is 28.

The square root of 123235561 is about 11101.1513366858. The cubic root of 123235561 is about 497.6362577207.

Adding to 123235561 its reverse (165532321), we get a palindrome (288767882).

The spelling of 123235561 in words is "one hundred twenty-three million, two hundred thirty-five thousand, five hundred sixty-one".