394991 has 4 divisors (see below), whose sum is σ = 415800. Its totient is φ = 374184.

The previous prime is 394987. The next prime is 394993. The reversal of 394991 is 199493.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 199493 = 7 ⋅28499.

It is a cyclic number.

It is not a de Polignac number, because 394991 - 2² = 394987 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (394993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10376 + ... + 10413.

It is an arithmetic number, because the mean of its divisors is an integer number (103950).

2³⁹⁴⁹⁹¹ is an apocalyptic number.

394991 is a deficient number, since it is larger than the sum of its proper divisors (20809).

394991 is a wasteful number, since it uses less digits than its factorization.

394991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20808.

The product of its digits is 8748, while the sum is 35.

The square root of 394991 is about 628.4830944425. The cubic root of 394991 is about 73.3717819499.

The spelling of 394991 in words is "three hundred ninety-four thousand, nine hundred ninety-one".