531209728 has 80 divisors (see below), whose sum is σ = 1225635840. Its totient is φ = 225294336.

The previous prime is 531209719. The next prime is 531209729. The reversal of 531209728 is 827902135.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (531209729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 368433 + ... + 369871.

It is an arithmetic number, because the mean of its divisors is an integer number (15320448).

Almost surely, 2^531209728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 531209728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (612817920).

531209728 is an abundant number, since it is smaller than the sum of its proper divisors (694426112).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

531209728 is a wasteful number, since it uses less digits than its factorization.

531209728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1567 (or 1551 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 37.

The square root of 531209728 is about 23047.9875043354. The cubic root of 531209728 is about 809.8824846028.

The spelling of 531209728 in words is "five hundred thirty-one million, two hundred nine thousand, seven hundred twenty-eight".