1311321220 has 48 divisors (see below), whose sum is σ = 3013754688. Its totient is φ = 475314560.

The previous prime is 1311321211. The next prime is 1311321229. The reversal of 1311321220 is 221231131.

It is an interprime number because it is at equal distance from previous prime (1311321211) and next prime (1311321229).

It is a junction number, because it is equal to n+sod(n) for n = 1311321194 and 1311321203.

It is not an unprimeable number, because it can be changed into a prime (1311321229) 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, 60339 + ... + 79141.

It is an arithmetic number, because the mean of its divisors is an integer number (62786556).

Almost surely, 2^1311321220 is an apocalyptic number.

1311321220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1311321220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1506877344).

1311321220 is an abundant number, since it is smaller than the sum of its proper divisors (1702433468).

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

1311321220 is a wasteful number, since it uses less digits than its factorization.

1311321220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19140 (or 19138 counting only the distinct ones).

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

The square root of 1311321220 is about 36212.1695014259. The cubic root of 1311321220 is about 1094.5519096798.

Adding to 1311321220 its reverse (221231131), we get a palindrome (1532552351).

The spelling of 1311321220 in words is "one billion, three hundred eleven million, three hundred twenty-one thousand, two hundred twenty".