198039857 has 2 divisors, whose sum is σ = 198039858. Its totient is φ = 198039856.

The previous prime is 198039791. The next prime is 198039859. The reversal of 198039857 is 758930891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 148815601 + 49224256 = 12199^2 + 7016^2 .

It is a cyclic number.

It is not a de Polignac number, because 198039857 - 2⁸ = 198039601 is a prime.

Together with 198039859, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (198039859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99019928 + 99019929.

It is an arithmetic number, because the mean of its divisors is an integer number (99019929).

Almost surely, 2^198039857 is an apocalyptic number.

It is an amenable number.

198039857 is a deficient number, since it is larger than the sum of its proper divisors (1).

198039857 is an equidigital number, since it uses as much as digits as its factorization.

198039857 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 544320, while the sum is 50.

The square root of 198039857 is about 14072.6634650303. The cubic root of 198039857 is about 582.8867743873.

The spelling of 198039857 in words is "one hundred ninety-eight million, thirty-nine thousand, eight hundred fifty-seven".