3999856 has 40 divisors (see below), whose sum is σ = 8999424. Its totient is φ = 1686720.

The previous prime is 3999851. The next prime is 3999859. The reversal of 3999856 is 6589993.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3999851) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7701 + ... + 8203.

Almost surely, 2^3999856 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 3999856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4499712).

3999856 is an abundant number, since it is smaller than the sum of its proper divisors (4999568).

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

3999856 is a wasteful number, since it uses less digits than its factorization.

3999856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 589 (or 583 counting only the distinct ones).

The product of its digits is 524880, while the sum is 49.

The square root of 3999856 is about 1999.9639996760. The cubic root of 3999856 is about 158.7382002927.

The spelling of 3999856 in words is "three million, nine hundred ninety-nine thousand, eight hundred fifty-six".