198979857 has 6 divisors (see below), whose sum is σ = 287415362. Its totient is φ = 132653232.

The previous prime is 198979841. The next prime is 198979867. The reversal of 198979857 is 758979891.

It can be written as a sum of positive squares in only one way, i.e., 158986881 + 39992976 = 12609^2 + 6324^2 .

It is not a de Polignac number, because 198979857 - 2⁴ = 198979841 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 198979794 and 198979803.

It is not an unprimeable number, because it can be changed into a prime (198979867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11054428 + ... + 11054445.

Almost surely, 2^198979857 is an apocalyptic number.

It is an amenable number.

198979857 is a deficient number, since it is larger than the sum of its proper divisors (88435505).

198979857 is a wasteful number, since it uses less digits than its factorization.

198979857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22108879 (or 22108876 counting only the distinct ones).

The product of its digits is 11430720, while the sum is 63.

The square root of 198979857 is about 14106.0220118927. The cubic root of 198979857 is about 583.8075468703.

The spelling of 198979857 in words is "one hundred ninety-eight million, nine hundred seventy-nine thousand, eight hundred fifty-seven".