131221221221 has 16 divisors (see below), whose sum is σ = 135171521088. Its totient is φ = 127340553600.

The previous prime is 131221221191. The next prime is 131221221223. The reversal of 131221221221 is 122122122131.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-131221221221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 131221221193 and 131221221202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131221221223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1314026 + ... + 1410356.

It is an arithmetic number, because the mean of its divisors is an integer number (8448220068).

Almost surely, 2^131221221221 is an apocalyptic number.

It is an amenable number.

131221221221 is a deficient number, since it is larger than the sum of its proper divisors (3950299867).

131221221221 is a wasteful number, since it uses less digits than its factorization.

131221221221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96692.

The product of its digits is 192, while the sum is 20.

Adding to 131221221221 its reverse (122122122131), we get a palindrome (253343343352).

The spelling of 131221221221 in words is "one hundred thirty-one billion, two hundred twenty-one million, two hundred twenty-one thousand, two hundred twenty-one".