198128123 has 2 divisors, whose sum is σ = 198128124. Its totient is φ = 198128122.

The previous prime is 198128107. The next prime is 198128137. The reversal of 198128123 is 321821891.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 198128123 - 2⁴ = 198128107 is a prime.

It is a super-3 number, since 3×198128123³ (a number of 26 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (198128023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99064061 + 99064062.

It is an arithmetic number, because the mean of its divisors is an integer number (99064062).

Almost surely, 2^198128123 is an apocalyptic number.

198128123 is a deficient number, since it is larger than the sum of its proper divisors (1).

198128123 is an equidigital number, since it uses as much as digits as its factorization.

198128123 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6912, while the sum is 35.

The square root of 198128123 is about 14075.7991957828. The cubic root of 198128123 is about 582.9733587128.

The spelling of 198128123 in words is "one hundred ninety-eight million, one hundred twenty-eight thousand, one hundred twenty-three".