394248509 has 4 divisors (see below), whose sum is σ = 396759804. Its totient is φ = 391737216.

The previous prime is 394248409. The next prime is 394248511. The reversal of 394248509 is 905842493.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 905842493 = 137 ⋅6611989.

It can be written as a sum of positive squares in 2 ways, for example, as 238548025 + 155700484 = 15445^2 + 12478^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-394248509 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 394248509.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (394248529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1255412 + ... + 1255725.

It is an arithmetic number, because the mean of its divisors is an integer number (99189951).

Almost surely, 2^394248509 is an apocalyptic number.

It is an amenable number.

394248509 is a deficient number, since it is larger than the sum of its proper divisors (2511295).

394248509 is a wasteful number, since it uses less digits than its factorization.

394248509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2511294.

The product of its (nonzero) digits is 311040, while the sum is 44.

The square root of 394248509 is about 19855.6921057917. The cubic root of 394248509 is about 733.2577916447.

The spelling of 394248509 in words is "three hundred ninety-four million, two hundred forty-eight thousand, five hundred nine".