1321378840 has 48 divisors (see below), whose sum is σ = 3014874000. Its totient is φ = 521227008.

The previous prime is 1321378829. The next prime is 1321378843. The reversal of 1321378840 is 488731231.

It is a self number, because there is not a number n which added to its sum of digits gives 1321378840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321378843) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 210061 + ... + 216259.

It is an arithmetic number, because the mean of its divisors is an integer number (62809875).

Almost surely, 2^1321378840 is an apocalyptic number.

1321378840 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 1321378840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1507437000).

1321378840 is an abundant number, since it is smaller than the sum of its proper divisors (1693495160).

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

1321378840 is an equidigital number, since it uses as much as digits as its factorization.

1321378840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6356 (or 6279 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 37.

The square root of 1321378840 is about 36350.7749573513. The cubic root of 1321378840 is about 1097.3431306347.

The spelling of 1321378840 in words is "one billion, three hundred twenty-one million, three hundred seventy-eight thousand, eight hundred forty".