394191809 has 8 divisors (see below), whose sum is σ = 444856320. Its totient is φ = 345998800.

The previous prime is 394191797. The next prime is 394191823. The reversal of 394191809 is 908191493.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 394191809 - 2¹² = 394187713 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 394191809.

It is not an unprimeable number, because it can be changed into a prime (394191829) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 617537 + ... + 618174.

It is an arithmetic number, because the mean of its divisors is an integer number (55607040).

Almost surely, 2^394191809 is an apocalyptic number.

It is an amenable number.

394191809 is a deficient number, since it is larger than the sum of its proper divisors (50664511).

394191809 is a wasteful number, since it uses less digits than its factorization.

394191809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1235751.

The product of its (nonzero) digits is 69984, while the sum is 44.

The square root of 394191809 is about 19854.2642522960. The cubic root of 394191809 is about 733.2226380896. Note that the first 3 decimals are identical.

The spelling of 394191809 in words is "three hundred ninety-four million, one hundred ninety-one thousand, eight hundred nine".