1221002010020 has 48 divisors (see below), whose sum is σ = 2762554933488. Its totient is φ = 450633646080.

The previous prime is 1221002010013. The next prime is 1221002010029. The reversal of 1221002010020 is 200102001221.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 228157164964 + 992844845056 = 477658^2 + 996416^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1221002009983 and 1221002010010.

It is not an unprimeable number, because it can be changed into a prime (1221002010029) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 436349 + ... + 1622468.

It is an arithmetic number, because the mean of its divisors is an integer number (57553227781).

Almost surely, 2^{1221002010020} is an apocalyptic number.

1221002010020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221002010020 is an abundant number, since it is smaller than the sum of its proper divisors (1541552923468).

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

1221002010020 is a wasteful number, since it uses less digits than its factorization.

1221002010020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2061120 (or 2061118 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 1221002010020 its reverse (200102001221), we get a palindrome (1421104011241).

The spelling of 1221002010020 in words is "one trillion, two hundred twenty-one billion, two million, ten thousand, twenty".