131220121221 has 24 divisors (see below), whose sum is σ = 218762079744. Its totient is φ = 74240517600.

The previous prime is 131220121141. The next prime is 131220121229. The reversal of 131220121221 is 122121022131.

It is not a de Polignac number, because 131220121221 - 2⁷ = 131220121093 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 131220121194 and 131220121203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131220121229) 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 23 ways as a sum of consecutive naturals, for example, 10304821 + ... + 10317546.

It is an arithmetic number, because the mean of its divisors is an integer number (9115086656).

Almost surely, 2^131220121221 is an apocalyptic number.

It is an amenable number.

131220121221 is a deficient number, since it is larger than the sum of its proper divisors (87541958523).

131220121221 is a wasteful number, since it uses less digits than its factorization.

131220121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20622481 (or 20622478 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

Adding to 131220121221 its reverse (122121022131), we get a palindrome (253341143352).

The spelling of 131220121221 in words is "one hundred thirty-one billion, two hundred twenty million, one hundred twenty-one thousand, two hundred twenty-one".