399491 has 2 divisors, whose sum is σ = 399492. Its totient is φ = 399490.

The previous prime is 399481. The next prime is 399493. The reversal of 399491 is 194993.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 399491 - 2¹⁰ = 398467 is a prime.

Together with 399493, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 9.

It is not a weakly prime, because it can be changed into another prime (399493) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199745 + 199746.

It is an arithmetic number, because the mean of its divisors is an integer number (199746).

2³⁹⁹⁴⁹¹ is an apocalyptic number.

399491 is a deficient number, since it is larger than the sum of its proper divisors (1).

399491 is an equidigital number, since it uses as much as digits as its factorization.

399491 is an odious number, because the sum of its binary digits is odd.

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

The square root of 399491 is about 632.0530041065. The cubic root of 399491 is about 73.6493638398.

The spelling of 399491 in words is "three hundred ninety-nine thousand, four hundred ninety-one".