123555557 has 2 divisors, whose sum is σ = 123555558. Its totient is φ = 123555556.

The previous prime is 123555529. The next prime is 123555569. The reversal of 123555557 is 755555321.

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., 64096036 + 59459521 = 8006^2 + 7711^2 .

It is a cyclic number.

It is not a de Polignac number, because 123555557 - 2¹⁰ = 123554533 is a prime.

It is a Chen prime.

It is a plaindrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 123555557.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (123555587) 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, 61777778 + 61777779.

It is an arithmetic number, because the mean of its divisors is an integer number (61777779).

Almost surely, 2^123555557 is an apocalyptic number.

It is an amenable number.

123555557 is a deficient number, since it is larger than the sum of its proper divisors (1).

123555557 is an equidigital number, since it uses as much as digits as its factorization.

123555557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 131250, while the sum is 38.

The square root of 123555557 is about 11115.5547319961. The cubic root of 123555557 is about 498.0666096394.

The spelling of 123555557 in words is "one hundred twenty-three million, five hundred fifty-five thousand, five hundred fifty-seven".