1221121011222 has 192 divisors, whose sum is σ = 3176618065920. Its totient is φ = 331684113600.

The previous prime is 1221121011221. The next prime is 1221121011239. The reversal of 1221121011222 is 2221101211221.

1221121011222 is a `hidden beast` number, since 1 + 221 + 1 + 210 + 11 + 222 = 666.

It is a super-2 number, since 2×1221121011222² (a number of 25 digits) contains 22 as substring.

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 = 1221121011195 and 1221121011204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221121011221) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 78475479 + ... + 78491037.

It is an arithmetic number, because the mean of its divisors is an integer number (16544885760).

Almost surely, 2^{1221121011222} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221121011222, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1588309032960).

1221121011222 is an abundant number, since it is smaller than the sum of its proper divisors (1955497054698).

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

1221121011222 is a wasteful number, since it uses less digits than its factorization.

1221121011222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15959 (or 15956 counting only the distinct ones).

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

Adding to 1221121011222 its reverse (2221101211221), we get a palindrome (3442222222443).

The spelling of 1221121011222 in words is "one trillion, two hundred twenty-one billion, one hundred twenty-one million, eleven thousand, two hundred twenty-two".