21111312222 has 192 divisors, whose sum is σ = 63076575744. Its totient is φ = 4924696320.

The previous prime is 21111312163. The next prime is 21111312227. The reversal of 21111312222 is 22221311112.

21111312222 is a `hidden beast` number, since 21 + 111 + 312 + 222 = 666.

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.

It is a junction number, because it is equal to n+sod(n) for n = 21111312195 and 21111312204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111312227) by changing a digit.

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 95 ways as a sum of consecutive naturals, for example, 650833 + ... + 682499.

It is an arithmetic number, because the mean of its divisors is an integer number (328523832).

Almost surely, 2^21111312222 is an apocalyptic number.

21111312222 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21111312222, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31538287872).

21111312222 is an abundant number, since it is smaller than the sum of its proper divisors (41965263522).

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

21111312222 is a wasteful number, since it uses less digits than its factorization.

21111312222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31743 (or 31740 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

Adding to 21111312222 its reverse (22221311112), we get a palindrome (43332623334).

It can be divided in two parts, 21111 and 312222, that added together give a palindrome (333333).

The spelling of 21111312222 in words is "twenty-one billion, one hundred eleven million, three hundred twelve thousand, two hundred twenty-two".