399861 has 24 divisors (see below), whose sum is σ = 721344. Its totient is φ = 207360.

The previous prime is 399853. The next prime is 399871. The reversal of 399861 is 168993.

It is not a de Polignac number, because 399861 - 2³ = 399853 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399851) 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 23 ways as a sum of consecutive naturals, for example, 405 + ... + 981.

It is an arithmetic number, because the mean of its divisors is an integer number (30056).

2³⁹⁹⁸⁶¹ is an apocalyptic number.

It is an amenable number.

399861 is a deficient number, since it is larger than the sum of its proper divisors (321483).

399861 is a wasteful number, since it uses less digits than its factorization.

399861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 601 (or 598 counting only the distinct ones).

The product of its digits is 11664, while the sum is 36.

The square root of 399861 is about 632.3456333367. The cubic root of 399861 is about 73.6720943110.

The spelling of 399861 in words is "three hundred ninety-nine thousand, eight hundred sixty-one".