399841 has 4 divisors (see below), whose sum is σ = 430612. Its totient is φ = 369072.

The previous prime is 399793. The next prime is 399851. The reversal of 399841 is 148993.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 108241 + 291600 = 329^2 + 540^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-399841 is a prime.

399841 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 399797 and 399806.

It is not an unprimeable number, because it can be changed into a prime (399851) 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, 15366 + ... + 15391.

It is an arithmetic number, because the mean of its divisors is an integer number (107653).

2³⁹⁹⁸⁴¹ is an apocalyptic number.

It is an amenable number.

399841 is a deficient number, since it is larger than the sum of its proper divisors (30771).

399841 is a wasteful number, since it uses less digits than its factorization.

399841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30770.

The product of its digits is 7776, while the sum is 34.

The square root of 399841 is about 632.3298190027. The cubic root of 399841 is about 73.6708659955.

The spelling of 399841 in words is "three hundred ninety-nine thousand, eight hundred forty-one".