6399871 has 4 divisors (see below), whose sum is σ = 6776352. Its totient is φ = 6023392.

The previous prime is 6399859. The next prime is 6399889. The reversal of 6399871 is 1789936.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 6399871 - 2¹¹ = 6397823 is a prime.

It is a Duffinian number.

6399871 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6399821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 188215 + ... + 188248.

It is an arithmetic number, because the mean of its divisors is an integer number (1694088).

Almost surely, 2^6399871 is an apocalyptic number.

6399871 is a deficient number, since it is larger than the sum of its proper divisors (376481).

6399871 is a wasteful number, since it uses less digits than its factorization.

6399871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 376480.

The product of its digits is 81648, while the sum is 43.

The square root of 6399871 is about 2529.7966321426. The cubic root of 6399871 is about 185.6623059091.

The spelling of 6399871 in words is "six million, three hundred ninety-nine thousand, eight hundred seventy-one".