1221002011218 has 128 divisors (see below), whose sum is σ = 2800112302080. Its totient is φ = 351335761920.

The previous prime is 1221002011211. The next prime is 1221002011249. The reversal of 1221002011218 is 8121102001221.

It is a super-2 number, since 2×1221002011218² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1221002011194 and 1221002011203.

It is not an unprimeable number, because it can be changed into a prime (1221002011211) 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, 404437713 + ... + 404440731.

It is an arithmetic number, because the mean of its divisors is an integer number (21875877360).

Almost surely, 2^{1221002011218} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221002011218, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1400056151040).

1221002011218 is an abundant number, since it is smaller than the sum of its proper divisors (1579110290862).

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

1221002011218 is a wasteful number, since it uses less digits than its factorization.

1221002011218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4912.

The product of its (nonzero) digits is 128, while the sum is 21.

Adding to 1221002011218 its reverse (8121102001221), we get a palindrome (9342104012439).

The spelling of 1221002011218 in words is "one trillion, two hundred twenty-one billion, two million, eleven thousand, two hundred eighteen".