1221011020020 has 192 divisors, whose sum is σ = 3783497195520. Its totient is φ = 291754176000.

The previous prime is 1221011019997. The next prime is 1221011020027. The reversal of 1221011020020 is 200201101221.

It is a super-2 number, since 2×1221011020020² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 1221011019978 and 1221011020005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221011020027) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 14824111 + ... + 14906249.

It is an arithmetic number, because the mean of its divisors is an integer number (19705714560).

Almost surely, 2^{1221011020020} is an apocalyptic number.

1221011020020 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 1221011020020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1891748597760).

1221011020020 is an abundant number, since it is smaller than the sum of its proper divisors (2562486175500).

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

1221011020020 is a wasteful number, since it uses less digits than its factorization.

1221011020020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82486 (or 82484 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 1221011020020 its reverse (200201101221), we get a palindrome (1421212121241).

The spelling of 1221011020020 in words is "one trillion, two hundred twenty-one billion, eleven million, twenty thousand, twenty".