1221120 has 120 divisors (see below), whose sum is σ = 4308876. Its totient is φ = 319488.

The previous prime is 1221119. The next prime is 1221131. The reversal of 1221120 is 211221.

It can be written as a sum of positive squares in 2 ways, for example, as 1218816 + 2304 = 1104^2 + 48^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a super-2 number, since 2×1221120² = 2982268108800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 23014 + ... + 23066.

2^1221120 is an apocalyptic number.

1221120 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 1221120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2154438).

1221120 is an abundant number, since it is smaller than the sum of its proper divisors (3087756).

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

1221120 is an equidigital number, since it uses as much as digits as its factorization.

1221120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82 (or 63 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 1221120 is about 1105.0429855892. The cubic root of 1221120 is about 106.8856611915.

Adding to 1221120 its reverse (211221), we get a palindrome (1432341).

The spelling of 1221120 in words is "one million, two hundred twenty-one thousand, one hundred twenty".