399851 has 2 divisors, whose sum is σ = 399852. Its totient is φ = 399850.

The previous prime is 399793. The next prime is 399853. The reversal of 399851 is 158993.

It is a strong prime.

It is an emirp because it is prime and its reverse (158993) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 399851 - 2⁶ = 399787 is a prime.

Together with 399853, it forms a pair of twin primes.

It is a Chen prime.

It is an Ulam number.

It is not a weakly prime, because it can be changed into another prime (399853) 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 as a sum of consecutive naturals, namely, 199925 + 199926.

It is an arithmetic number, because the mean of its divisors is an integer number (199926).

2³⁹⁹⁸⁵¹ is an apocalyptic number.

399851 is a deficient number, since it is larger than the sum of its proper divisors (1).

399851 is an equidigital number, since it uses as much as digits as its factorization.

399851 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9720, while the sum is 35.

The square root of 399851 is about 632.3377262191. The cubic root of 399851 is about 73.6714801584.

The spelling of 399851 in words is "three hundred ninety-nine thousand, eight hundred fifty-one".