231221211312 has 480 divisors, whose sum is σ = 796365029376. Its totient is φ = 56438553600.

The previous prime is 231221211301. The next prime is 231221211323. The reversal of 231221211312 is 213112122132.

It is an interprime number because it is at equal distance from previous prime (231221211301) and next prime (231221211323).

It is a super-2 number, since 2×231221211312² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 40484137 + ... + 40489847.

Almost surely, 2^231221211312 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 231221211312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (398182514688).

231221211312 is an abundant number, since it is smaller than the sum of its proper divisors (565143818064).

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

231221211312 is a wasteful number, since it uses less digits than its factorization.

231221211312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5809 (or 5790 counting only the distinct ones).

The product of its digits is 288, while the sum is 21.

Adding to 231221211312 its reverse (213112122132), we get a palindrome (444333333444).

The spelling of 231221211312 in words is "two hundred thirty-one billion, two hundred twenty-one million, two hundred eleven thousand, three hundred twelve".