1001221221020 has 48 divisors (see below), whose sum is σ = 2105324937408. Its totient is φ = 399962949120.

The previous prime is 1001221220999. The next prime is 1001221221023. The reversal of 1001221221020 is 201221221001.

It is a junction number, because it is equal to n+sod(n) for n = 1001221220986 and 1001221221004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001221221023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 131372810 + ... + 131380430.

It is an arithmetic number, because the mean of its divisors is an integer number (43860936196).

Almost surely, 2^{1001221221020} is an apocalyptic number.

1001221221020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1001221221020 is an abundant number, since it is smaller than the sum of its proper divisors (1104103716388).

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

1001221221020 is a wasteful number, since it uses less digits than its factorization.

1001221221020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15390 (or 15388 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 1001221221020 its reverse (201221221001), we get a palindrome (1202442442021).

The spelling of 1001221221020 in words is "one trillion, one billion, two hundred twenty-one million, two hundred twenty-one thousand, twenty".