1221111120 has 80 divisors (see below), whose sum is σ = 3915999360. Its totient is φ = 314399232.

The previous prime is 1221111097. The next prime is 1221111167. The reversal of 1221111120 is 211111221.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×1221111120² = 2982224734775308800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 1221111096 and 1221111105.

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, 80764 + ... + 94683.

It is an arithmetic number, because the mean of its divisors is an integer number (48949992).

Almost surely, 2^1221111120 is an apocalyptic number.

1221111120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221111120 is an abundant number, since it is smaller than the sum of its proper divisors (2694888240).

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

1221111120 is a wasteful number, since it uses less digits than its factorization.

1221111120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 175492 (or 175486 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 12.

The square root of 1221111120 is about 34944.4004097938. The cubic root of 1221111120 is about 1068.8540209960.

Adding to 1221111120 its reverse (211111221), we get a palindrome (1432222341).

The spelling of 1221111120 in words is "one billion, two hundred twenty-one million, one hundred eleven thousand, one hundred twenty".