509401 has 4 divisors (see below), whose sum is σ = 517072. Its totient is φ = 501732.

The previous prime is 509393. The next prime is 509413. The reversal of 509401 is 104905.

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: 104905 = 5 ⋅20981.

It is a cyclic number.

It is not a de Polignac number, because 509401 - 2³ = 509393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (509441) 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, 3735 + ... + 3868.

It is an arithmetic number, because the mean of its divisors is an integer number (129268).

2⁵⁰⁹⁴⁰¹ is an apocalyptic number.

It is an amenable number.

509401 is a deficient number, since it is larger than the sum of its proper divisors (7671).

509401 is an equidigital number, since it uses as much as digits as its factorization.

509401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7670.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 509401 is about 713.7233357541. The cubic root of 509401 is about 79.8644057239.

Subtracting from 509401 its reverse (104905), we obtain a square (404496 = 636²).

The spelling of 509401 in words is "five hundred nine thousand, four hundred one".