531311220 has 288 divisors, whose sum is σ = 1842632064. Its totient is φ = 122803200.

The previous prime is 531311213. The next prime is 531311239. The reversal of 531311220 is 22113135.

531311220 is a `hidden beast` number, since 531 + 3 + 112 + 20 = 666.

It is a super-2 number, since 2×531311220² = 564583224995776800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 531311193 and 531311202.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 6401299 + ... + 6401381.

It is an arithmetic number, because the mean of its divisors is an integer number (6398028).

Almost surely, 2^531311220 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 531311220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (921316032).

531311220 is an abundant number, since it is smaller than the sum of its proper divisors (1311320844).

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

531311220 is a wasteful number, since it uses less digits than its factorization.

531311220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223 (or 218 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 18.

The square root of 531311220 is about 23050.1891532369. The cubic root of 531311220 is about 809.9340595612.

Adding to 531311220 its reverse (22113135), we get a palindrome (553424355).

The spelling of 531311220 in words is "five hundred thirty-one million, three hundred eleven thousand, two hundred twenty".