3999865 has 8 divisors (see below), whose sum is σ = 4838400. Its totient is φ = 3174192.

The previous prime is 3999859. The next prime is 3999871. The reversal of 3999865 is 5689993.

3999865 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (3999859) and next prime (3999871).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 3999865 - 2¹⁷ = 3868793 is a prime.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 2515 + ... + 3784.

It is an arithmetic number, because the mean of its divisors is an integer number (604800).

Almost surely, 2^3999865 is an apocalyptic number.

It is an amenable number.

3999865 is a deficient number, since it is larger than the sum of its proper divisors (838535).

3999865 is a wasteful number, since it uses less digits than its factorization.

3999865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6431.

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

The square root of 3999865 is about 1999.9662497152. The cubic root of 3999865 is about 158.7383193505.

The spelling of 3999865 in words is "three million, nine hundred ninety-nine thousand, eight hundred sixty-five".