198878450209 has 2 divisors, whose sum is σ = 198878450210. Its totient is φ = 198878450208.

The previous prime is 198878450201. The next prime is 198878450219. The reversal of 198878450209 is 902054878891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 146275651600 + 52602798609 = 382460^2 + 229353^2 .

It is a cyclic number.

It is not a de Polignac number, because 198878450209 - 2³ = 198878450201 is a prime.

It is not a weakly prime, because it can be changed into another prime (198878450201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99439225104 + 99439225105.

It is an arithmetic number, because the mean of its divisors is an integer number (99439225105).

Almost surely, 2^198878450209 is an apocalyptic number.

It is an amenable number.

198878450209 is a deficient number, since it is larger than the sum of its proper divisors (1).

198878450209 is an equidigital number, since it uses as much as digits as its factorization.

198878450209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11612160, while the sum is 61.

The spelling of 198878450209 in words is "one hundred ninety-eight billion, eight hundred seventy-eight million, four hundred fifty thousand, two hundred nine".