211211221220 has 24 divisors (see below), whose sum is σ = 444446932608. Its totient is φ = 84312418400.

The previous prime is 211211221129. The next prime is 211211221223. The reversal of 211211221220 is 22122112112.

211211221220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×211211221220² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (211211221223) 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 7 ways as a sum of consecutive naturals, for example, 10744316 + ... + 10763955.

It is an arithmetic number, because the mean of its divisors is an integer number (18518622192).

Almost surely, 2^211211221220 is an apocalyptic number.

211211221220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

211211221220 is an abundant number, since it is smaller than the sum of its proper divisors (233235711388).

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

211211221220 is a wasteful number, since it uses less digits than its factorization.

211211221220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21508771 (or 21508769 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 211211221220 its reverse (22122112112), we get a palindrome (233333333332).

The spelling of 211211221220 in words is "two hundred eleven billion, two hundred eleven million, two hundred twenty-one thousand, two hundred twenty".