531215440 has 80 divisors (see below), whose sum is σ = 1415088000. Its totient is φ = 181670400.

The previous prime is 531215431. The next prime is 531215441. The reversal of 531215440 is 44512135.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (531215441) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 278490 + ... + 280390.

It is an arithmetic number, because the mean of its divisors is an integer number (17688600).

Almost surely, 2^531215440 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 531215440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (707544000).

531215440 is an abundant number, since it is smaller than the sum of its proper divisors (883872560).

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

531215440 is a wasteful number, since it uses less digits than its factorization.

531215440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2420 (or 2414 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 531215440 is about 23048.1114193766. Note that the first 3 decimals coincide. The cubic root of 531215440 is about 809.8853874312.

Adding to 531215440 its reverse (44512135), we get a palindrome (575727575).

The spelling of 531215440 in words is "five hundred thirty-one million, two hundred fifteen thousand, four hundred forty".