1321321220 has 24 divisors (see below), whose sum is σ = 2776032000. Its totient is φ = 528288992.

The previous prime is 1321321219. The next prime is 1321321223. The reversal of 1321321220 is 221231231.

It is not an unprimeable number, because it can be changed into a prime (1321321223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34211 + ... + 61749.

It is an arithmetic number, because the mean of its divisors is an integer number (115668000).

Almost surely, 2^1321321220 is an apocalyptic number.

1321321220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1321321220 is an abundant number, since it is smaller than the sum of its proper divisors (1454710780).

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

1321321220 is a wasteful number, since it uses less digits than its factorization.

1321321220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29947 (or 29945 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 1321321220 is about 36349.9823933933. The cubic root of 1321321220 is about 1097.3271801673.

Adding to 1321321220 its reverse (221231231), we get a palindrome (1542552451).

The spelling of 1321321220 in words is "one billion, three hundred twenty-one million, three hundred twenty-one thousand, two hundred twenty".