198728857 has 2 divisors, whose sum is σ = 198728858. Its totient is φ = 198728856.

The previous prime is 198728839. The next prime is 198728891. The reversal of 198728857 is 758827891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 103002201 + 95726656 = 10149^2 + 9784^2 .

It is a cyclic number.

It is not a de Polignac number, because 198728857 - 2¹⁹ = 198204569 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 198728798 and 198728807.

It is not a weakly prime, because it can be changed into another prime (198728807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99364428 + 99364429.

It is an arithmetic number, because the mean of its divisors is an integer number (99364429).

Almost surely, 2^198728857 is an apocalyptic number.

It is an amenable number.

198728857 is a deficient number, since it is larger than the sum of its proper divisors (1).

198728857 is an equidigital number, since it uses as much as digits as its factorization.

198728857 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2257920, while the sum is 55.

The square root of 198728857 is about 14097.1222949934. The cubic root of 198728857 is about 583.5619653079.

The spelling of 198728857 in words is "one hundred ninety-eight million, seven hundred twenty-eight thousand, eight hundred fifty-seven".