198979009 has 2 divisors, whose sum is σ = 198979010. Its totient is φ = 198979008.

The previous prime is 198978973. The next prime is 198979043. The reversal of 198979009 is 900979891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 182169009 + 16810000 = 13497^2 + 4100^2 .

It is a cyclic number.

It is not a de Polignac number, because 198979009 - 2¹³ = 198970817 is a prime.

It is not a weakly prime, because it can be changed into another prime (198979069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99489504 + 99489505.

It is an arithmetic number, because the mean of its divisors is an integer number (99489505).

Almost surely, 2^198979009 is an apocalyptic number.

It is an amenable number.

198979009 is a deficient number, since it is larger than the sum of its proper divisors (1).

198979009 is an equidigital number, since it uses as much as digits as its factorization.

198979009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 367416, while the sum is 52.

The square root of 198979009 is about 14105.9919537762. The cubic root of 198979009 is about 583.8067175242.

The spelling of 198979009 in words is "one hundred ninety-eight million, nine hundred seventy-nine thousand, nine".