121211220 has 48 divisors (see below), whose sum is σ = 365500800. Its totient is φ = 29836416.

The previous prime is 121211183. The next prime is 121211221. The reversal of 121211220 is 22112121.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 121211196 and 121211205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121211221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 76920 + ... + 78479.

It is an arithmetic number, because the mean of its divisors is an integer number (7614600).

Almost surely, 2^121211220 is an apocalyptic number.

121211220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121211220 is an abundant number, since it is smaller than the sum of its proper divisors (244289580).

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

121211220 is a wasteful number, since it uses less digits than its factorization.

121211220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155424 (or 155422 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 121211220 is about 11009.5967228596. The cubic root of 121211220 is about 494.8963766357.

Adding to 121211220 its reverse (22112121), we get a palindrome (143323341).

Subtracting from 121211220 its reverse (22112121), we obtain a palindrome (99099099).

The spelling of 121211220 in words is "one hundred twenty-one million, two hundred eleven thousand, two hundred twenty".