8391409 has 4 divisors (see below), whose sum is σ = 9036916. Its totient is φ = 7745904.

The previous prime is 8391401. The next prime is 8391413. The reversal of 8391409 is 9041938.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2241009 + 6150400 = 1497^2 + 2480^2 .

It is a cyclic number.

It is not a de Polignac number, because 8391409 - 2³ = 8391401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8391401) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 322734 + ... + 322759.

It is an arithmetic number, because the mean of its divisors is an integer number (2259229).

Almost surely, 2^8391409 is an apocalyptic number.

It is an amenable number.

8391409 is a deficient number, since it is larger than the sum of its proper divisors (645507).

8391409 is a wasteful number, since it uses less digits than its factorization.

8391409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 645506.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 8391409 is about 2896.7928817919. The cubic root of 8391409 is about 203.2099472392.

The spelling of 8391409 in words is "eight million, three hundred ninety-one thousand, four hundred nine".