1121021220 has 192 divisors, whose sum is σ = 3523709952. Its totient is φ = 264000000.

The previous prime is 1121021197. The next prime is 1121021263. The reversal of 1121021220 is 221201211.

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 = 1121021196 and 1121021205.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4466095 + ... + 4466345.

It is an arithmetic number, because the mean of its divisors is an integer number (18352656).

Almost surely, 2^1121021220 is an apocalyptic number.

1121021220 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 1121021220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1761854976).

1121021220 is an abundant number, since it is smaller than the sum of its proper divisors (2402688732).

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

1121021220 is a wasteful number, since it uses less digits than its factorization.

1121021220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 442 (or 440 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 1121021220 is about 33481.6549770169. The cubic root of 1121021220 is about 1038.8143601307.

Adding to 1121021220 its reverse (221201211), we get a palindrome (1342222431).

Subtracting from 1121021220 its reverse (221201211), we obtain a square (899820009 = 29997²).

The spelling of 1121021220 in words is "one billion, one hundred twenty-one million, twenty-one thousand, two hundred twenty".