399744 has 48 divisors (see below), whose sum is σ = 1153620. Its totient is φ = 132864.

The previous prime is 399739. The next prime is 399757. The reversal of 399744 is 447993.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a zygodrome in base 2.

It is a junction number, because it is equal to n+sod(n) for n = 399699 and 399708.

It is a congruent number.

It is an unprimeable number.

399744 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 979 + ... + 1325.

2³⁹⁹⁷⁴⁴ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 399744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (576810).

399744 is an abundant number, since it is smaller than the sum of its proper divisors (753876).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

399744 is a wasteful number, since it uses less digits than its factorization.

399744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 367 (or 352 counting only the distinct ones).

The product of its digits is 27216, while the sum is 36.

The square root of 399744 is about 632.2531138713. The cubic root of 399744 is about 73.6649080839.

The spelling of 399744 in words is "three hundred ninety-nine thousand, seven hundred forty-four".