1231161320 has 16 divisors (see below), whose sum is σ = 2770113060. Its totient is φ = 492464512.

The previous prime is 1231161313. The next prime is 1231161341. The reversal of 1231161320 is 231611321.

It can be written as a sum of positive squares in 2 ways, for example, as 1208674756 + 22486564 = 34766^2 + 4742^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 1231161292 and 1231161301.

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 3 ways as a sum of consecutive naturals, for example, 15389477 + ... + 15389556.

Almost surely, 2^1231161320 is an apocalyptic number.

1231161320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1231161320 is an abundant number, since it is smaller than the sum of its proper divisors (1538951740).

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

1231161320 is a wasteful number, since it uses less digits than its factorization.

1231161320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30779044 (or 30779040 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 1231161320 is about 35087.9084586129. The cubic root of 1231161320 is about 1071.7783685465.

Adding to 1231161320 its reverse (231611321), we get a palindrome (1462772641).

The spelling of 1231161320 in words is "one billion, two hundred thirty-one million, one hundred sixty-one thousand, three hundred twenty".