1221020200000 has 84 divisors (see below), whose sum is σ = 3028509108324. Its totient is φ = 488408000000.

The previous prime is 1221020199989. The next prime is 1221020200079. The reversal of 1221020200000 is 20201221.

It can be written as a sum of positive squares in 6 ways, for example, as 895627533376 + 325392666624 = 946376^2 + 570432^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a self number, because there is not a number n which added to its sum of digits gives 1221020200000.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2852551 + ... + 3252550.

It is an arithmetic number, because the mean of its divisors is an integer number (36053679861).

Almost surely, 2^{1221020200000} is an apocalyptic number.

1221020200000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221020200000 is an abundant number, since it is smaller than the sum of its proper divisors (1807488908324).

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

1221020200000 is an frugal number, since it uses more digits than its factorization.

1221020200000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6105138 (or 6105108 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

Adding to 1221020200000 its reverse (20201221), we get a palindrome (1221040401221).

The spelling of 1221020200000 in words is "one trillion, two hundred twenty-one billion, twenty million, two hundred thousand".