398772509 has 2 divisors, whose sum is σ = 398772510. Its totient is φ = 398772508.

The previous prime is 398772469. The next prime is 398772511. The reversal of 398772509 is 905277893.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 223951225 + 174821284 = 14965^2 + 13222^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-398772509 is a prime.

Together with 398772511, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (398772559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199386254 + 199386255.

It is an arithmetic number, because the mean of its divisors is an integer number (199386255).

Almost surely, 2^398772509 is an apocalyptic number.

It is an amenable number.

398772509 is a deficient number, since it is larger than the sum of its proper divisors (1).

398772509 is an equidigital number, since it uses as much as digits as its factorization.

398772509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 952560, while the sum is 50.

The square root of 398772509 is about 19969.2891460863. The cubic root of 398772509 is about 736.0518415407.

The spelling of 398772509 in words is "three hundred ninety-eight million, seven hundred seventy-two thousand, five hundred nine".