1321442640 has 640 divisors, whose sum is σ = 5669637120. Its totient is φ = 276037632.

The previous prime is 1321442597. The next prime is 1321442641. The reversal of 1321442640 is 462441231.

It is a happy number.

1321442640 is a `hidden beast` number, since 1 + 3 + 2 + 14 + 4 + 2 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321442641) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 13623072 + ... + 13623168.

It is an arithmetic number, because the mean of its divisors is an integer number (8858808).

Almost surely, 2^1321442640 is an apocalyptic number.

1321442640 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 1321442640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2834818560).

1321442640 is an abundant number, since it is smaller than the sum of its proper divisors (4348194480).

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

1321442640 is a wasteful number, since it uses less digits than its factorization.

1321442640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196 (or 184 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 27.

The square root of 1321442640 is about 36351.6525071420. The cubic root of 1321442640 is about 1097.3607913193.

Adding to 1321442640 its reverse (462441231), we get a palindrome (1783883871).

The spelling of 1321442640 in words is "one billion, three hundred twenty-one million, four hundred forty-two thousand, six hundred forty".