398669009 has 2 divisors, whose sum is σ = 398669010. Its totient is φ = 398669008.

The previous prime is 398668999. The next prime is 398669059. The reversal of 398669009 is 900966893.

It is an a-pointer prime, because the next prime (398669059) can be obtained adding 398669009 to its sum of digits (50).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 338560000 + 60109009 = 18400^2 + 7753^2 .

It is a cyclic number.

It is not a de Polignac number, because 398669009 - 2¹² = 398664913 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (398669059) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199334504 + 199334505.

It is an arithmetic number, because the mean of its divisors is an integer number (199334505).

Almost surely, 2^398669009 is an apocalyptic number.

It is an amenable number.

398669009 is a deficient number, since it is larger than the sum of its proper divisors (1).

398669009 is an equidigital number, since it uses as much as digits as its factorization.

398669009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 629856, while the sum is 50.

The square root of 398669009 is about 19966.6974985850. The cubic root of 398669009 is about 735.9881561431.

The spelling of 398669009 in words is "three hundred ninety-eight million, six hundred sixty-nine thousand, nine".