531121221 has 24 divisors (see below), whose sum is σ = 802279296. Its totient is φ = 337946400.

The previous prime is 531121169. The next prime is 531121277. The reversal of 531121221 is 122121135.

531121221 is a `hidden beast` number, since 531 + 12 + 122 + 1 = 666.

It is not a de Polignac number, because 531121221 - 2¹⁰ = 531120197 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 531121194 and 531121203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (531123221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 101571 + ... + 106671.

It is an arithmetic number, because the mean of its divisors is an integer number (33428304).

Almost surely, 2^531121221 is an apocalyptic number.

It is an amenable number.

531121221 is a deficient number, since it is larger than the sum of its proper divisors (271158075).

531121221 is a wasteful number, since it uses less digits than its factorization.

531121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5633 (or 5630 counting only the distinct ones).

The product of its digits is 120, while the sum is 18.

The square root of 531121221 is about 23046.0673651710. The cubic root of 531121221 is about 809.8375028397.

Adding to 531121221 its reverse (122121135), we get a palindrome (653242356).

The spelling of 531121221 in words is "five hundred thirty-one million, one hundred twenty-one thousand, two hundred twenty-one".