1221011112120 has 64 divisors (see below), whose sum is σ = 3669148800000. Its totient is φ = 325059366528.

The previous prime is 1221011112109. The next prime is 1221011112163. The reversal of 1221011112120 is 212111101221.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 1221011112120.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8421520 + ... + 8565279.

It is an arithmetic number, because the mean of its divisors is an integer number (57330450000).

Almost surely, 2^{1221011112120} is an apocalyptic number.

1221011112120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221011112120 is an abundant number, since it is smaller than the sum of its proper divisors (2448137687880).

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

1221011112120 is a wasteful number, since it uses less digits than its factorization.

1221011112120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16987412 (or 16987408 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 1221011112120 its reverse (212111101221), we get a palindrome (1433122213341).

The spelling of 1221011112120 in words is "one trillion, two hundred twenty-one billion, eleven million, one hundred twelve thousand, one hundred twenty".