1221220202220 has 336 divisors, whose sum is σ = 3888585616608. Its totient is φ = 321993584640.

The previous prime is 1221220202203. The next prime is 1221220202221. The reversal of 1221220202220 is 222020221221.

1221220202220 is a `hidden beast` number, since 1 + 2 + 21 + 220 + 202 + 220 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 1221220202193 and 1221220202202.

It is not an unprimeable number, because it can be changed into a prime (1221220202221) by changing a digit.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 605462652 + ... + 605464668.

It is an arithmetic number, because the mean of its divisors is an integer number (11573171478).

Almost surely, 2^{1221220202220} is an apocalyptic number.

1221220202220 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 1221220202220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1944292808304).

1221220202220 is an abundant number, since it is smaller than the sum of its proper divisors (2667365414388).

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

1221220202220 is a wasteful number, since it uses less digits than its factorization.

1221220202220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2492 (or 2475 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

Adding to 1221220202220 its reverse (222020221221), we get a palindrome (1443240423441).

The spelling of 1221220202220 in words is "one trillion, two hundred twenty-one billion, two hundred twenty million, two hundred two thousand, two hundred twenty".