1331323440 has 80 divisors (see below), whose sum is σ = 4134780000. Its totient is φ = 354359296.

The previous prime is 1331323429. The next prime is 1331323459. The reversal of 1331323440 is 443231331.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 1331323440.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 131686 + ... + 141434.

It is an arithmetic number, because the mean of its divisors is an integer number (51684750).

Almost surely, 2^1331323440 is an apocalyptic number.

1331323440 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 1331323440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2067390000).

1331323440 is an abundant number, since it is smaller than the sum of its proper divisors (2803456560).

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

1331323440 is a wasteful number, since it uses less digits than its factorization.

1331323440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10334 (or 10328 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 24.

The square root of 1331323440 is about 36487.3051896136. The cubic root of 1331323440 is about 1100.0890947119.

Adding to 1331323440 its reverse (443231331), we get a palindrome (1774554771).

The spelling of 1331323440 in words is "one billion, three hundred thirty-one million, three hundred twenty-three thousand, four hundred forty".