1312211220 has 96 divisors (see below), whose sum is σ = 3777755520. Its totient is φ = 340139520.

The previous prime is 1312211213. The next prime is 1312211239. The reversal of 1312211220 is 221122131.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 1312211220.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 589710 + ... + 591930.

It is an arithmetic number, because the mean of its divisors is an integer number (39351620).

Almost surely, 2^1312211220 is an apocalyptic number.

1312211220 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 1312211220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1888877760).

1312211220 is an abundant number, since it is smaller than the sum of its proper divisors (2465544300).

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

1312211220 is a wasteful number, since it uses less digits than its factorization.

1312211220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2505 (or 2503 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 1312211220 is about 36224.4561035773. The cubic root of 1312211220 is about 1094.7994795558.

Adding to 1312211220 its reverse (221122131), we get a palindrome (1533333351).

It can be divided in two parts, 13122 and 11220, that added together give a palindrome (24342).

The spelling of 1312211220 in words is "one billion, three hundred twelve million, two hundred eleven thousand, two hundred twenty".