1221020121020 has 72 divisors (see below), whose sum is σ = 2987389442016. Its totient is φ = 417988212096.

The previous prime is 1221020120993. The next prime is 1221020121047. The reversal of 1221020121020 is 201210201221.

It is an interprime number because it is at equal distance from previous prime (1221020120993) and next prime (1221020121047).

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a junction number, because it is equal to n+sod(n) for n = 1221020120986 and 1221020121004.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 328799 + ... + 1596918.

It is an arithmetic number, because the mean of its divisors is an integer number (41491520028).

Almost surely, 2^{1221020121020} is an apocalyptic number.

1221020121020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221020121020 is an abundant number, since it is smaller than the sum of its proper divisors (1766369320996).

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

1221020121020 is a wasteful number, since it uses less digits than its factorization.

1221020121020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1926387 (or 1926378 counting only the distinct ones).

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

Adding to 1221020121020 its reverse (201210201221), we get a palindrome (1422230322241).

The spelling of 1221020121020 in words is "one trillion, two hundred twenty-one billion, twenty million, one hundred twenty-one thousand, twenty".