121221220218 has 64 divisors (see below), whose sum is σ = 291858816000. Its totient is φ = 32789401344.

The previous prime is 121221220217. The next prime is 121221220223. The reversal of 121221220218 is 812022122121.

It is a super-2 number, since 2×121221220218² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (121221220213) 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 31 ways as a sum of consecutive naturals, for example, 1137213 + ... + 1239231.

It is an arithmetic number, because the mean of its divisors is an integer number (4560294000).

Almost surely, 2^121221220218 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121221220218, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (145929408000).

121221220218 is an abundant number, since it is smaller than the sum of its proper divisors (170637595782).

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

121221220218 is a wasteful number, since it uses less digits than its factorization.

121221220218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103539.

The product of its (nonzero) digits is 512, while the sum is 24.

Adding to 121221220218 its reverse (812022122121), we get a palindrome (933243342339).

The spelling of 121221220218 in words is "one hundred twenty-one billion, two hundred twenty-one million, two hundred twenty thousand, two hundred eighteen".