1331231220 has 96 divisors (see below), whose sum is σ = 4518138240. Its totient is φ = 322721280.

The previous prime is 1331231197. The next prime is 1331231261. The reversal of 1331231220 is 221321331.

1331231220 is a `hidden beast` number, since 1 + 331 + 2 + 312 + 20 = 666.

It is a super-2 number, since 2×1331231220² = 3544353122205376800, which contains 22 as substring.

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 = 1331231193 and 1331231202.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 106117 + ... + 117996.

It is an arithmetic number, because the mean of its divisors is an integer number (47063940).

Almost surely, 2^1331231220 is an apocalyptic number.

1331231220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1331231220 is an abundant number, since it is smaller than the sum of its proper divisors (3186907020).

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

1331231220 is a wasteful number, since it uses less digits than its factorization.

1331231220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 224142 (or 224134 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 1331231220 is about 36486.0414405290. The cubic root of 1331231220 is about 1100.0636932816.

Adding to 1331231220 its reverse (221321331), we get a palindrome (1552552551).

The spelling of 1331231220 in words is "one billion, three hundred thirty-one million, two hundred thirty-one thousand, two hundred twenty".