6820509 has 4 divisors (see below), whose sum is σ = 9094016. Its totient is φ = 4547004.

The previous prime is 6820493. The next prime is 6820511. The reversal of 6820509 is 9050286.

6820509 is nontrivially palindromic in base 11.

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 not a de Polignac number, because 6820509 - 2⁴ = 6820493 is a prime.

It is a D-number.

It is a Duffinian number.

6820509 is an undulating number in base 11.

6820509 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6820559) 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, 1136749 + ... + 1136754.

It is an arithmetic number, because the mean of its divisors is an integer number (2273504).

Almost surely, 2^6820509 is an apocalyptic number.

It is an amenable number.

6820509 is a deficient number, since it is larger than the sum of its proper divisors (2273507).

6820509 is a wasteful number, since it uses less digits than its factorization.

6820509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2273506.

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 6820509 is about 2611.6104227086. The cubic root of 6820509 is about 189.6439221981.

The spelling of 6820509 in words is "six million, eight hundred twenty thousand, five hundred nine".