1221011220121 has 12 divisors (see below), whose sum is σ = 1549483626960. Its totient is φ = 951437313960.

The previous prime is 1221011220061. The next prime is 1221011220127. The reversal of 1221011220121 is 1210221101221.

It is not a de Polignac number, because 1221011220121 - 2⁷ = 1221011219993 is a prime.

It is a super-2 number, since 2×1221011220121² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221011220095 and 1221011220104.

It is not an unprimeable number, because it can be changed into a prime (1221011220127) 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 11 ways as a sum of consecutive naturals, for example, 1132662931 + ... + 1132664008.

It is an arithmetic number, because the mean of its divisors is an integer number (129123635580).

Almost surely, 2^{1221011220121} is an apocalyptic number.

1221011220121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221011220121 is a deficient number, since it is larger than the sum of its proper divisors (328472406839).

1221011220121 is a wasteful number, since it uses less digits than its factorization.

1221011220121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2265326964 (or 2265326957 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 1221011220121 its reverse (1210221101221), we get a palindrome (2431232321342).

The spelling of 1221011220121 in words is "one trillion, two hundred twenty-one billion, eleven million, two hundred twenty thousand, one hundred twenty-one".