198409 has 2 divisors, whose sum is σ = 198410. Its totient is φ = 198408.

The previous prime is 198397. The next prime is 198413. The reversal of 198409 is 904891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 138384 + 60025 = 372^2 + 245^2 .

It is a cyclic number.

It is not a de Polignac number, because 198409 - 2⁵ = 198377 is a prime.

It is a super-2 number, since 2×198409² = 78732262562, which contains 22 as substring.

It is a Chen prime.

It is an Ulam number.

It is not a weakly prime, because it can be changed into another prime (198439) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99204 + 99205.

It is an arithmetic number, because the mean of its divisors is an integer number (99205).

2¹⁹⁸⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

198409 is a deficient number, since it is larger than the sum of its proper divisors (1).

198409 is an equidigital number, since it uses as much as digits as its factorization.

198409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 198409 is about 445.4312517101. The cubic root of 198409 is about 58.3248713349.

The spelling of 198409 in words is "one hundred ninety-eight thousand, four hundred nine".