399776 has 36 divisors (see below), whose sum is σ = 875826. Its totient is φ = 178560.

The previous prime is 399769. The next prime is 399781. The reversal of 399776 is 677993.

It can be written as a sum of positive squares in only one way, i.e., 384400 + 15376 = 620^2 + 124^2 .

It is an unprimeable number.

399776 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 in 5 ways as a sum of consecutive naturals, for example, 12881 + ... + 12911.

2³⁹⁹⁷⁷⁶ 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 399776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (437913).

399776 is an abundant number, since it is smaller than the sum of its proper divisors (476050).

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

399776 is a wasteful number, since it uses less digits than its factorization.

399776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85 (or 46 counting only the distinct ones).

The product of its digits is 71442, while the sum is 41.

The square root of 399776 is about 632.2784196855. The cubic root of 399776 is about 73.6668736871. Note that the first 3 decimals are identical.

The spelling of 399776 in words is "three hundred ninety-nine thousand, seven hundred seventy-six".