7999864 has 8 divisors (see below), whose sum is σ = 14999760. Its totient is φ = 3999928.

The previous prime is 7999847. The next prime is 7999909. The reversal of 7999864 is 4689997.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

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 as a sum of consecutive naturals, namely, 499984 + ... + 499999.

It is an arithmetic number, because the mean of its divisors is an integer number (1874970).

Almost surely, 2^7999864 is an apocalyptic number.

It is an amenable number.

7999864 is a deficient number, since it is larger than the sum of its proper divisors (6999896).

7999864 is a wasteful number, since it uses less digits than its factorization.

7999864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 999989 (or 999985 counting only the distinct ones).

The product of its digits is 979776, while the sum is 52.

The square root of 7999864 is about 2828.4030830135. The cubic root of 7999864 is about 199.9988666602.

The spelling of 7999864 in words is "seven million, nine hundred ninety-nine thousand, eight hundred sixty-four".