393944209 has 4 divisors (see below), whose sum is σ = 396778480. Its totient is φ = 391109940.

The previous prime is 393944189. The next prime is 393944237. The reversal of 393944209 is 902449393.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 393944209 - 2¹³ = 393936017 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (393944609) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1416927 + ... + 1417204.

It is an arithmetic number, because the mean of its divisors is an integer number (99194620).

Almost surely, 2^393944209 is an apocalyptic number.

It is an amenable number.

393944209 is a deficient number, since it is larger than the sum of its proper divisors (2834271).

393944209 is a wasteful number, since it uses less digits than its factorization.

393944209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2834270.

The product of its (nonzero) digits is 209952, while the sum is 43.

The square root of 393944209 is about 19848.0278365383. The cubic root of 393944209 is about 733.0690885187.

The spelling of 393944209 in words is "three hundred ninety-three million, nine hundred forty-four thousand, two hundred nine".