211221222120 has 96 divisors (see below), whose sum is σ = 687099460320. Its totient is φ = 56273927040.

The previous prime is 211221222109. The next prime is 211221222137. The reversal of 211221222120 is 21222122112.

It is a happy number.

211221222120 is a `hidden beast` number, since 211 + 2 + 212 + 221 + 20 = 666.

It is a super-2 number, since 2×211221222120² (a number of 23 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 = 211221222093 and 211221222102.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 123867 + ... + 661653.

It is an arithmetic number, because the mean of its divisors is an integer number (7157286045).

Almost surely, 2^211221222120 is an apocalyptic number.

211221222120 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 211221222120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (343549730160).

211221222120 is an abundant number, since it is smaller than the sum of its proper divisors (475878238200).

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

211221222120 is a wasteful number, since it uses less digits than its factorization.

211221222120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 538895 (or 538888 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 211221222120 its reverse (21222122112), we get a palindrome (232443344232).

The spelling of 211221222120 in words is "two hundred eleven billion, two hundred twenty-one million, two hundred twenty-two thousand, one hundred twenty".