1221002120020 has 48 divisors (see below), whose sum is σ = 2714208456960. Its totient is φ = 460592931456.

The previous prime is 1221002120003. The next prime is 1221002120021. The reversal of 1221002120020 is 200212001221.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221002120021) 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 15 ways as a sum of consecutive naturals, for example, 24453852 + ... + 24503731.

It is an arithmetic number, because the mean of its divisors is an integer number (56546009520).

Almost surely, 2^{1221002120020} is an apocalyptic number.

1221002120020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221002120020 is an abundant number, since it is smaller than the sum of its proper divisors (1493206336940).

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

1221002120020 is a wasteful number, since it uses less digits than its factorization.

1221002120020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48957664 (or 48957662 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 1221002120020 its reverse (200212001221), we get a palindrome (1421214121241).

The spelling of 1221002120020 in words is "one trillion, two hundred twenty-one billion, two million, one hundred twenty thousand, twenty".