1311221320 has 16 divisors (see below), whose sum is σ = 2950248060. Its totient is φ = 524488512.

The previous prime is 1311221299. The next prime is 1311221321. The reversal of 1311221320 is 231221131.

It can be written as a sum of positive squares in 2 ways, for example, as 1071776644 + 239444676 = 32738^2 + 15474^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1311221294 and 1311221303.

It is not an unprimeable number, because it can be changed into a prime (1311221321) 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, 16390227 + ... + 16390306.

Almost surely, 2^1311221320 is an apocalyptic number.

1311221320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1311221320 is an abundant number, since it is smaller than the sum of its proper divisors (1639026740).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1311221320 is a wasteful number, since it uses less digits than its factorization.

1311221320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32780544 (or 32780540 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 1311221320 is about 36210.7901046083. The cubic root of 1311221320 is about 1094.5241136649.

Adding to 1311221320 its reverse (231221131), we get a palindrome (1542442451).

The spelling of 1311221320 in words is "one billion, three hundred eleven million, two hundred twenty-one thousand, three hundred twenty".