6440843136 has 512 divisors, whose sum is σ = 22619520000. Its totient is φ = 1576599552.

The previous prime is 6440843119. The next prime is 6440843137. The reversal of 6440843136 is 6313480446.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a junction number, because it is equal to n+sod(n) for n = 6440843094 and 6440843103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440843137) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 59090250 + ... + 59090358.

It is an arithmetic number, because the mean of its divisors is an integer number (44178750).

Almost surely, 2^6440843136 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6440843136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11309760000).

6440843136 is an abundant number, since it is smaller than the sum of its proper divisors (16178676864).

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

6440843136 is a wasteful number, since it uses less digits than its factorization.

6440843136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 254 (or 242 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 39.

The square root of 6440843136 is about 80254.8636283185. The cubic root of 6440843136 is about 1860.5766832489.

The spelling of 6440843136 in words is "six billion, four hundred forty million, eight hundred forty-three thousand, one hundred thirty-six".