1221202220 has 96 divisors (see below), whose sum is σ = 3099672576. Its totient is φ = 395251200.

The previous prime is 1221202183. The next prime is 1221202223. The reversal of 1221202220 is 222021221.

It is a super-3 number, since 3×1221202220³ (a number of 28 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a junction number, because it is equal to n+sod(n) for n = 1221202195 and 1221202204.

It is not an unprimeable number, because it can be changed into a prime (1221202223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 174509 + ... + 181371.

It is an arithmetic number, because the mean of its divisors is an integer number (32288256).

Almost surely, 2^1221202220 is an apocalyptic number.

1221202220 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 1221202220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1549836288).

1221202220 is an abundant number, since it is smaller than the sum of its proper divisors (1878470356).

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

1221202220 is a wasteful number, since it uses less digits than its factorization.

1221202220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6951 (or 6949 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 1221202220 is about 34945.7038847410. The cubic root of 1221202220 is about 1068.8806006628.

Adding to 1221202220 its reverse (222021221), we get a palindrome (1443223441).

The spelling of 1221202220 in words is "one billion, two hundred twenty-one million, two hundred two thousand, two hundred twenty".