1221320 has 32 divisors (see below), whose sum is σ = 2894400. Its totient is φ = 462528.

The previous prime is 1221299. The next prime is 1221373. The reversal of 1221320 is 231221.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44 + ... + 1563.

It is an arithmetic number, because the mean of its divisors is an integer number (90450).

2^1221320 is an apocalyptic number.

1221320 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 1221320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1447200).

1221320 is an abundant number, since it is smaller than the sum of its proper divisors (1673080).

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

1221320 is a wasteful number, since it uses less digits than its factorization.

1221320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1637 (or 1633 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 1221320 is about 1105.1334761014. The cubic root of 1221320 is about 106.8914962624.

Adding to 1221320 its reverse (231221), we get a palindrome (1452541).

Subtracting from 1221320 its reverse (231221), we obtain a palindrome (990099).

The spelling of 1221320 in words is "one million, two hundred twenty-one thousand, three hundred twenty".