231310121220 has 144 divisors (see below), whose sum is σ = 710377078320. Its totient is φ = 60917760000.

The previous prime is 231310121219. The next prime is 231310121249. The reversal of 231310121220 is 22121013132.

231310121220 is a `hidden beast` number, since 2 + 313 + 10 + 121 + 220 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 129409989696 + 101900131524 = 359736^2 + 319218^2 .

It is a super-2 number, since 2×231310121220² (a number of 24 digits) 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 = 231310121193 and 231310121202.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7274316 + ... + 7306044.

It is an arithmetic number, because the mean of its divisors is an integer number (4933174155).

Almost surely, 2^231310121220 is an apocalyptic number.

231310121220 is a gapful number since it is divisible by the number (20) 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 231310121220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (355188539160).

231310121220 is an abundant number, since it is smaller than the sum of its proper divisors (479066957100).

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

231310121220 is a wasteful number, since it uses less digits than its factorization.

231310121220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32246 (or 32241 counting only the distinct ones).

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

Adding to 231310121220 its reverse (22121013132), we get a palindrome (253431134352).

The spelling of 231310121220 in words is "two hundred thirty-one billion, three hundred ten million, one hundred twenty-one thousand, two hundred twenty".