531390209 has 4 divisors (see below), whose sum is σ = 607303104. Its totient is φ = 455477316.

The previous prime is 531390191. The next prime is 531390221. The reversal of 531390209 is 902093135.

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: 902093135 = 5 ⋅180418627.

It is not a de Polignac number, because 531390209 - 2²⁰ = 530341633 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (531390239) 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, 37956437 + ... + 37956450.

It is an arithmetic number, because the mean of its divisors is an integer number (151825776).

Almost surely, 2^531390209 is an apocalyptic number.

It is an amenable number.

531390209 is a deficient number, since it is larger than the sum of its proper divisors (75912895).

531390209 is an equidigital number, since it uses as much as digits as its factorization.

531390209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75912894.

The product of its (nonzero) digits is 7290, while the sum is 32.

The square root of 531390209 is about 23051.9025028304. The cubic root of 531390209 is about 809.9741946765.

The spelling of 531390209 in words is "five hundred thirty-one million, three hundred ninety thousand, two hundred nine".