6520409 has 4 divisors (see below), whose sum is σ = 7451904. Its totient is φ = 5588916.

The previous prime is 6520403. The next prime is 6520411. The reversal of 6520409 is 9040256.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 6520409 - 2⁸ = 6520153 is a prime.

It is a super-3 number, since 3×6520409³ (a number of 21 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6520403) 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, 465737 + ... + 465750.

It is an arithmetic number, because the mean of its divisors is an integer number (1862976).

Almost surely, 2^6520409 is an apocalyptic number.

It is an amenable number.

6520409 is a deficient number, since it is larger than the sum of its proper divisors (931495).

6520409 is an equidigital number, since it uses as much as digits as its factorization.

6520409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 931494.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 6520409 is about 2553.5091540858. The cubic root of 6520409 is about 186.8206789464.

The spelling of 6520409 in words is "six million, five hundred twenty thousand, four hundred nine".