1311431220 has 72 divisors (see below), whose sum is σ = 4339651680. Its totient is φ = 317922240.

The previous prime is 1311431179. The next prime is 1311431239. The reversal of 1311431220 is 221341131.

1311431220 is a `hidden beast` number, since 1 + 3 + 11 + 431 + 220 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 1311431193 and 1311431202.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 329190 + ... + 333149.

It is an arithmetic number, because the mean of its divisors is an integer number (60272940).

Almost surely, 2^1311431220 is an apocalyptic number.

1311431220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1311431220 is an abundant number, since it is smaller than the sum of its proper divisors (3028220460).

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

1311431220 is a wasteful number, since it uses less digits than its factorization.

1311431220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 662365 (or 662360 counting only the distinct ones).

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

The square root of 1311431220 is about 36213.6882960021. The cubic root of 1311431220 is about 1094.5825142695.

Adding to 1311431220 its reverse (221341131), we get a palindrome (1532772351).

The spelling of 1311431220 in words is "one billion, three hundred eleven million, four hundred thirty-one thousand, two hundred twenty".