1321330440 has 128 divisors (see below), whose sum is σ = 4210704000. Its totient is φ = 330559488.

The previous prime is 1321330337. The next prime is 1321330447. The reversal of 1321330440 is 440331231.

It is not an unprimeable number, because it can be changed into a prime (1321330447) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 772306 + ... + 774014.

It is an arithmetic number, because the mean of its divisors is an integer number (32896125).

Almost surely, 2^1321330440 is an apocalyptic number.

1321330440 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 1321330440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2105352000).

1321330440 is an abundant number, since it is smaller than the sum of its proper divisors (2889373560).

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

1321330440 is a wasteful number, since it uses less digits than its factorization.

1321330440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2119 (or 2115 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 21.

The square root of 1321330440 is about 36350.1092157919. The cubic root of 1321330440 is about 1097.3297324947.

Adding to 1321330440 its reverse (440331231), we get a palindrome (1761661671).

The spelling of 1321330440 in words is "one billion, three hundred twenty-one million, three hundred thirty thousand, four hundred forty".