509869 has 4 divisors (see below), whose sum is σ = 516096. Its totient is φ = 503644.

The previous prime is 509867. The next prime is 509879. The reversal of 509869 is 968905.

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 509869 - 2¹ = 509867 is a prime.

It is a super-2 number, since 2×509869² = 519932794322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (509863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2989 + ... + 3154.

It is an arithmetic number, because the mean of its divisors is an integer number (129024).

2⁵⁰⁹⁸⁶⁹ is an apocalyptic number.

It is an amenable number.

509869 is a deficient number, since it is larger than the sum of its proper divisors (6227).

509869 is an equidigital number, since it uses as much as digits as its factorization.

509869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6226.

The product of its (nonzero) digits is 19440, while the sum is 37.

The square root of 509869 is about 714.0511186183. The cubic root of 509869 is about 79.8888560760. Note that the first 4 decimals are identical.

Multiplying 509869 by its sum of digits (37), we get a triangular number (18865153 = T₆₁₄₂).

It can be divided in two parts, 509 and 869, that added together give a triangular number (1378 = T₅₂).

The spelling of 509869 in words is "five hundred nine thousand, eight hundred sixty-nine".