1221220331131 has 4 divisors (see below), whose sum is σ = 1249620803992. Its totient is φ = 1192819858272.

The previous prime is 1221220331101. The next prime is 1221220331171. The reversal of 1221220331131 is 1311330221221.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 1221220331131 - 2¹¹ = 1221220329083 is a prime.

It is a super-2 number, since 2×1221220331131² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221220331101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14200236366 + ... + 14200236451.

It is an arithmetic number, because the mean of its divisors is an integer number (312405200998).

Almost surely, 2^{1221220331131} is an apocalyptic number.

1221220331131 is a deficient number, since it is larger than the sum of its proper divisors (28400472861).

1221220331131 is an equidigital number, since it uses as much as digits as its factorization.

1221220331131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28400472860.

The product of its (nonzero) digits is 432, while the sum is 22.

Adding to 1221220331131 its reverse (1311330221221), we get a palindrome (2532550552352).

The spelling of 1221220331131 in words is "one trillion, two hundred twenty-one billion, two hundred twenty million, three hundred thirty-one thousand, one hundred thirty-one".