7981866 has 12 divisors (see below), whose sum is σ = 17294082. Its totient is φ = 2660616.

The previous prime is 7981859. The next prime is 7981867. The reversal of 7981866 is 6681897.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 7209225 + 772641 = 2685^2 + 879^2 .

It is not an unprimeable number, because it can be changed into a prime (7981867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 221701 + ... + 221736.

Almost surely, 2^7981866 is an apocalyptic number.

7981866 is an abundant number, since it is smaller than the sum of its proper divisors (9312216).

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

7981866 is a wasteful number, since it uses less digits than its factorization.

7981866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 443445 (or 443442 counting only the distinct ones).

The product of its digits is 145152, while the sum is 45.

The square root of 7981866 is about 2825.2196374795. The cubic root of 7981866 is about 199.8487690081.

The spelling of 7981866 in words is "seven million, nine hundred eighty-one thousand, eight hundred sixty-six".