531440809 has 3 divisors (see below), whose sum is σ = 531463863. Its totient is φ = 531417756.

The previous prime is 531440807. The next prime is 531440839. The reversal of 531440809 is 908044135.

The square root of 531440809 is 23053.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 406627225 + 124813584 = 20165^2 + 11172^2 .

It is not a de Polignac number, because 531440809 - 2¹ = 531440807 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (531440807) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 11527 + ... + 34579.

It is an arithmetic number, because the mean of its divisors is an integer number (177154621).

Almost surely, 2^531440809 is an apocalyptic number.

531440809 is the 23053-rd square number.

531440809 is the 11527-th centered octagonal number.

It is an amenable number.

531440809 is a deficient number, since it is larger than the sum of its proper divisors (23054).

531440809 is an frugal number, since it uses more digits than its factorization.

531440809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46106 (or 23053 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 34.

The cubic root of 531440809 is about 809.9999029619. Note that the first 4 decimals are identical.

The spelling of 531440809 in words is "five hundred thirty-one million, four hundred forty thousand, eight hundred nine".