1211111121220 has 576 divisors, whose sum is σ = 3680307767808. Its totient is φ = 324605952000.

The previous prime is 1211111121217. The next prime is 1211111121221. The reversal of 1211111121220 is 221211111121.

It is a junction number, because it is equal to n+sod(n) for n = 1211111121194 and 1211111121203.

It is not an unprimeable number, because it can be changed into a prime (1211111121221) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 378116139 + ... + 378119341.

It is an arithmetic number, because the mean of its divisors is an integer number (6389423208).

Almost surely, 2^{1211111121220} is an apocalyptic number.

1211111121220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1211111121220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1840153883904).

1211111121220 is an abundant number, since it is smaller than the sum of its proper divisors (2469196646588).

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

1211111121220 is a wasteful number, since it uses less digits than its factorization.

1211111121220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3372 (or 3359 counting only the distinct ones).

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

Adding to 1211111121220 its reverse (221211111121), we get a palindrome (1432322232341).

It can be divided in two parts, 1211111 and 121220, that added together give a palindrome (1332331).

The spelling of 1211111121220 in words is "one trillion, two hundred eleven billion, one hundred eleven million, one hundred twenty-one thousand, two hundred twenty".