31111221312 has 140 divisors (see below), whose sum is σ = 93392020480.
Its totient is φ = 10239001344.
The previous prime is 31111221311. The next prime is 31111221353. The reversal of 31111221312 is 21312211113.
Adding to 31111221312 its reverse (21312211113), we get a palindrome (52423432425).
It is a Harshad number since it is a multiple of its sum of digits (18).
It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.
It is an insolite number, because it is divisible by the sum (36) and by the product (5184) of the squares of its digits.
It is not an unprimeable number, because it can be changed into a prime (31111221311) by changing a digit.
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 19 ways as a sum of consecutive naturals, for example, 371553 + ... + 447519.
Almost surely, 231111221312 is an apocalyptic number.
31111221312 is a gapful number since it is divisible by the number (32) 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 31111221312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46696010240).
31111221312 is an abundant number, since it is smaller than the sum of its proper divisors (62280799168).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
31111221312 is an equidigital number, since it uses as much as digits as its factorization.
31111221312 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 76070 (or 76051 counting only the distinct ones).
The product of its digits is 72, while the sum is 18.
The spelling of 31111221312 in words is "thirty-one billion, one hundred eleven million, two hundred twenty-one thousand, three hundred twelve".