311220013221 has 24 divisors (see below), whose sum is σ = 484432839800. Its totient is φ = 191396255616.

The previous prime is 311220013219. The next prime is 311220013231. The reversal of 311220013221 is 122310022113.

311220013221 is a `hidden beast` number, since 311 + 2 + 200 + 132 + 21 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 8351400996 + 302868612225 = 91386^2 + 550335^2 .

It is not a de Polignac number, because 311220013221 - 2¹ = 311220013219 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 311220013194 and 311220013203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (311220013231) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 677386 + ... + 1039851.

Almost surely, 2^311220013221 is an apocalyptic number.

It is an amenable number.

311220013221 is a deficient number, since it is larger than the sum of its proper divisors (173212826579).

311220013221 is a wasteful number, since it uses less digits than its factorization.

311220013221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1718805 (or 1718802 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 311220013221 its reverse (122310022113), we get a palindrome (433530035334).

The spelling of 311220013221 in words is "three hundred eleven billion, two hundred twenty million, thirteen thousand, two hundred twenty-one".