7999866 has 48 divisors (see below), whose sum is σ = 19977984. Its totient is φ = 2266272.

The previous prime is 7999847. The next prime is 7999909. The reversal of 7999866 is 6689997.

7999866 is digitally balanced in base 8, because in such base it contains all the possibile digits an equal number of times.

7999866 is strictly pandigital in base 8.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21615 + ... + 21981.

It is an arithmetic number, because the mean of its divisors is an integer number (416208).

Almost surely, 2^7999866 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 7999866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9988992).

7999866 is an abundant number, since it is smaller than the sum of its proper divisors (11978118).

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

7999866 is a wasteful number, since it uses less digits than its factorization.

7999866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 555 (or 552 counting only the distinct ones).

The product of its digits is 1469664, while the sum is 54.

The square root of 7999866 is about 2828.4034365698. The cubic root of 7999866 is about 199.9988833271.

The spelling of 7999866 in words is "seven million, nine hundred ninety-nine thousand, eight hundred sixty-six".