1321131440 has 20 divisors (see below), whose sum is σ = 3071630784. Its totient is φ = 528452544.

The previous prime is 1321131437. The next prime is 1321131451. The reversal of 1321131440 is 441311231.

It is a tau number, because it is divible by the number of its divisors (20).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8256992 + ... + 8257151.

Almost surely, 2^1321131440 is an apocalyptic number.

1321131440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1321131440 is an abundant number, since it is smaller than the sum of its proper divisors (1750499344).

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

1321131440 is a wasteful number, since it uses less digits than its factorization.

1321131440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16514156 (or 16514150 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 1321131440 is about 36347.3718444677. The cubic root of 1321131440 is about 1097.2746416626.

Adding to 1321131440 its reverse (441311231), we get a palindrome (1762442671).

The spelling of 1321131440 in words is "one billion, three hundred twenty-one million, one hundred thirty-one thousand, four hundred forty".