131223021221 has 4 divisors (see below), whose sum is σ = 131272598112. Its totient is φ = 131173444332.

The previous prime is 131223021203. The next prime is 131223021229. The reversal of 131223021221 is 122120322131.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 122120322131 = 132371 ⋅922561.

It is a cyclic number.

It is not a de Polignac number, because 131223021221 - 2³⁰ = 130149279397 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 131223021193 and 131223021202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131223021229) 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 3 ways as a sum of consecutive naturals, for example, 24784475 + ... + 24789768.

It is an arithmetic number, because the mean of its divisors is an integer number (32818149528).

Almost surely, 2^131223021221 is an apocalyptic number.

It is an amenable number.

131223021221 is a deficient number, since it is larger than the sum of its proper divisors (49576891).

131223021221 is an equidigital number, since it uses as much as digits as its factorization.

131223021221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49576890.

The product of its (nonzero) digits is 288, while the sum is 20.

Adding to 131223021221 its reverse (122120322131), we get a palindrome (253343343352).

The spelling of 131223021221 in words is "one hundred thirty-one billion, two hundred twenty-three million, twenty-one thousand, two hundred twenty-one".