211212220 has 96 divisors (see below), whose sum is σ = 487710720. Its totient is φ = 76581120.

The previous prime is 211212203. The next prime is 211212241. The reversal of 211212220 is 22212112.

It is a happy number.

211212220 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×211212220² = 89221203754656800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 211212220.

It is a congruent number.

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 31 ways as a sum of consecutive naturals, for example, 947029 + ... + 947251.

It is an arithmetic number, because the mean of its divisors is an integer number (5080320).

Almost surely, 2^211212220 is an apocalyptic number.

211212220 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 211212220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (243855360).

211212220 is an abundant number, since it is smaller than the sum of its proper divisors (276498500).

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

211212220 is a wasteful number, since it uses less digits than its factorization.

211212220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 355 (or 353 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 211212220 is about 14533.1421241244. The cubic root of 211212220 is about 595.5337065685.

Adding to 211212220 its reverse (22212112), we get a palindrome (233424332).

The spelling of 211212220 in words is "two hundred eleven million, two hundred twelve thousand, two hundred twenty".