978209 has 2 divisors, whose sum is σ = 978210. Its totient is φ = 978208.

The previous prime is 978203. The next prime is 978217. The reversal of 978209 is 902879.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 672400 + 305809 = 820^2 + 553^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-978209 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a nialpdrome in base 16.

It is not a weakly prime, because it can be changed into another prime (978203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 489104 + 489105.

It is an arithmetic number, because the mean of its divisors is an integer number (489105).

2⁹⁷⁸²⁰⁹ is an apocalyptic number.

It is an amenable number.

978209 is a deficient number, since it is larger than the sum of its proper divisors (1).

978209 is an equidigital number, since it uses as much as digits as its factorization.

978209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9072, while the sum is 35.

The square root of 978209 is about 989.0444883826. The cubic root of 978209 is about 99.2682924321.

It can be divided in two parts, 978 and 209, that multiplied together give a palindrome (204402).

The spelling of 978209 in words is "nine hundred seventy-eight thousand, two hundred nine".