1221011212122 has 128 divisors (see below), whose sum is σ = 2962026144000. Its totient is φ = 370587398400.

The previous prime is 1221011212093. The next prime is 1221011212159. The reversal of 1221011212122 is 2212121101221.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 1221011212095 and 1221011212104.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 19040629 + ... + 19104647.

It is an arithmetic number, because the mean of its divisors is an integer number (23140829250).

Almost surely, 2^{1221011212122} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221011212122, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1481013072000).

1221011212122 is an abundant number, since it is smaller than the sum of its proper divisors (1741014931878).

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

1221011212122 is a wasteful number, since it uses less digits than its factorization.

1221011212122 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64413 (or 64407 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 1221011212122 its reverse (2212121101221), we get a palindrome (3433132313343).

The spelling of 1221011212122 in words is "one trillion, two hundred twenty-one billion, eleven million, two hundred twelve thousand, one hundred twenty-two".