531221213422221 has 16 divisors (see below), whose sum is σ = 809502941324928. Its totient is φ = 303546355200000.

The previous prime is 531221213422217. The next prime is 531221213422243. The reversal of 531221213422221 is 122224312122135.

It is a happy number.

It is not a de Polignac number, because 531221213422221 - 2² = 531221213422217 is a prime.

It is a super-3 number, since 3×531221213422221³ (a number of 45 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (531221213423221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 358572280 + ... + 360050721.

It is an arithmetic number, because the mean of its divisors is an integer number (50593933832808).

Almost surely, 2^{531221213422221} is an apocalyptic number.

It is an amenable number.

531221213422221 is a deficient number, since it is larger than the sum of its proper divisors (278281727902707).

531221213422221 is a wasteful number, since it uses less digits than its factorization.

531221213422221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 718658212.

The product of its digits is 23040, while the sum is 33.

Adding to 531221213422221 its reverse (122224312122135), we get a palindrome (653445525544356).

The spelling of 531221213422221 in words is "five hundred thirty-one trillion, two hundred twenty-one billion, two hundred thirteen million, four hundred twenty-two thousand, two hundred twenty-one".