8391009 has 16 divisors (see below), whose sum is σ = 12346560. Its totient is φ = 5026560.

The previous prime is 8391001. The next prime is 8391011. The reversal of 8391009 is 9001938.

It is a happy number.

It is not a de Polignac number, because 8391009 - 2³ = 8391001 is a prime.

It is not an unprimeable number, because it can be changed into a prime (8391001) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1509 + ... + 4365.

It is an arithmetic number, because the mean of its divisors is an integer number (771660).

Almost surely, 2^8391009 is an apocalyptic number.

8391009 is a gapful number since it is divisible by the number (89) formed by its first and last digit.

It is an amenable number.

8391009 is a deficient number, since it is larger than the sum of its proper divisors (3955551).

8391009 is a wasteful number, since it uses less digits than its factorization.

8391009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2960.

The product of its (nonzero) digits is 1944, while the sum is 30.

The square root of 8391009 is about 2896.7238390982. The cubic root of 8391009 is about 203.2067183309.

The spelling of 8391009 in words is "eight million, three hundred ninety-one thousand, nine".