131211221 has 16 divisors (see below), whose sum is σ = 136745280. Its totient is φ = 125836800.

The previous prime is 131211181. The next prime is 131211229. The reversal of 131211221 is 122112131.

It is a cyclic number.

It is not a de Polignac number, because 131211221 - 2¹⁴ = 131194837 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 131211196 and 131211205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131211229) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 577910 + ... + 578136.

It is an arithmetic number, because the mean of its divisors is an integer number (8546580).

Almost surely, 2^131211221 is an apocalyptic number.

It is an amenable number.

131211221 is a deficient number, since it is larger than the sum of its proper divisors (5534059).

131211221 is a wasteful number, since it uses less digits than its factorization.

131211221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 484.

The product of its digits is 24, while the sum is 14.

The square root of 131211221 is about 11454.7466580453. The cubic root of 131211221 is about 508.1481228941.

Adding to 131211221 its reverse (122112131), we get a palindrome (253323352).

The spelling of 131211221 in words is "one hundred thirty-one million, two hundred eleven thousand, two hundred twenty-one".