121221021220 has 144 divisors (see below), whose sum is σ = 281034609408. Its totient is φ = 43659244800.

The previous prime is 121221021199. The next prime is 121221021223. The reversal of 121221021220 is 22120122121.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 121221021194 and 121221021203.

It is not an unprimeable number, because it can be changed into a prime (121221021223) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 136663617 + ... + 136664503.

It is an arithmetic number, because the mean of its divisors is an integer number (1951629232).

Almost surely, 2^121221021220 is an apocalyptic number.

121221021220 is a gapful number since it is divisible by the number (10) 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 121221021220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140517304704).

121221021220 is an abundant number, since it is smaller than the sum of its proper divisors (159813588188).

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

121221021220 is a wasteful number, since it uses less digits than its factorization.

121221021220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1178 (or 1117 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 121221021220 its reverse (22120122121), we get a palindrome (143341143341).

The spelling of 121221021220 in words is "one hundred twenty-one billion, two hundred twenty-one million, twenty-one thousand, two hundred twenty".