7999009 has 6 divisors (see below), whose sum is σ = 8362466. Its totient is φ = 7650720.

The previous prime is 7998979. The next prime is 7999051. The reversal of 7999009 is 9009997.

It can be written as a sum of positive squares in only one way, i.e., 5832225 + 2166784 = 2415^2 + 1472^2 .

It is a de Polignac number, because none of the positive numbers 2^k-7999009 is a prime.

It is a Duffinian number.

7999009 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (7999709) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7032 + ... + 8089.

Almost surely, 2^7999009 is an apocalyptic number.

It is an amenable number.

7999009 is a deficient number, since it is larger than the sum of its proper divisors (363457).

7999009 is a wasteful number, since it uses less digits than its factorization.

7999009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15167 (or 15144 counting only the distinct ones).

The product of its (nonzero) digits is 45927, while the sum is 43.

The square root of 7999009 is about 2828.2519336155. The cubic root of 7999009 is about 199.9917413256.

The spelling of 7999009 in words is "seven million, nine hundred ninety-nine thousand, nine".