1321333220 has 12 divisors (see below), whose sum is σ = 2774799804. Its totient is φ = 528533280.

The previous prime is 1321333213. The next prime is 1321333229. The reversal of 1321333220 is 223331231.

It can be written as a sum of positive squares in 2 ways, for example, as 236421376 + 1084911844 = 15376^2 + 32938^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 66066661 = 1321333220 / (1 + 3 + 2 + 1 + 3 + 3 + 3 + 2 + 2 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 1321333192 and 1321333201.

It is not an unprimeable number, because it can be changed into a prime (1321333229) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33033311 + ... + 33033350.

It is an arithmetic number, because the mean of its divisors is an integer number (231233317).

Almost surely, 2^1321333220 is an apocalyptic number.

1321333220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1321333220 is an abundant number, since it is smaller than the sum of its proper divisors (1453466584).

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

1321333220 is a wasteful number, since it uses less digits than its factorization.

1321333220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66066670 (or 66066668 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 20.

The square root of 1321333220 is about 36350.1474549967. The cubic root of 1321333220 is about 1097.3305020661.

Adding to 1321333220 its reverse (223331231), we get a palindrome (1544664451).

The spelling of 1321333220 in words is "one billion, three hundred twenty-one million, three hundred thirty-three thousand, two hundred twenty".