509381 has 4 divisors (see below), whose sum is σ = 531552. Its totient is φ = 487212.

The previous prime is 509363. The next prime is 509389. The reversal of 509381 is 183905.

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, and also an emirpimes, since its reverse is a distinct semiprime: 183905 = 5 ⋅36781.

It is a cyclic number.

It is not a de Polignac number, because 509381 - 2⁶ = 509317 is a prime.

It is a super-2 number, since 2×509381² = 518938006322, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 509381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (509389) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11051 + ... + 11096.

It is an arithmetic number, because the mean of its divisors is an integer number (132888).

2⁵⁰⁹³⁸¹ is an apocalyptic number.

It is an amenable number.

509381 is a deficient number, since it is larger than the sum of its proper divisors (22171).

509381 is a wasteful number, since it uses less digits than its factorization.

509381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22170.

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 509381 is about 713.7093245853. The cubic root of 509381 is about 79.8633605035.

The spelling of 509381 in words is "five hundred nine thousand, three hundred eighty-one".