656509 has 4 divisors (see below), whose sum is σ = 750304. Its totient is φ = 562716.

The previous prime is 656483. The next prime is 656519. The reversal of 656509 is 905656.

It is a happy number.

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 656509 - 2¹³ = 648317 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (656519) 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, 46887 + ... + 46900.

It is an arithmetic number, because the mean of its divisors is an integer number (187576).

2⁶⁵⁶⁵⁰⁹ is an apocalyptic number.

It is an amenable number.

656509 is a deficient number, since it is larger than the sum of its proper divisors (93795).

656509 is an equidigital number, since it uses as much as digits as its factorization.

656509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93794.

The product of its (nonzero) digits is 8100, while the sum is 31.

The square root of 656509 is about 810.2524298020. The cubic root of 656509 is about 86.9120968839.

The spelling of 656509 in words is "six hundred fifty-six thousand, five hundred nine".