6444381643 has 8 divisors (see below), whose sum is σ = 7421230080. Its totient is φ = 5481588840.

The previous prime is 6444381637. The next prime is 6444381679. The reversal of 6444381643 is 3461834446.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 6444381643 - 2⁵ = 6444381611 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6444381643.

It is not an unprimeable number, because it can be changed into a prime (6444381683) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3512923 + ... + 3514756.

It is an arithmetic number, because the mean of its divisors is an integer number (927653760).

Almost surely, 2^6444381643 is an apocalyptic number.

6444381643 is a deficient number, since it is larger than the sum of its proper divisors (976848437).

6444381643 is a wasteful number, since it uses less digits than its factorization.

6444381643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7027817.

The product of its digits is 663552, while the sum is 43.

The square root of 6444381643 is about 80276.9060377890. The cubic root of 6444381643 is about 1860.9173456016.

The spelling of 6444381643 in words is "six billion, four hundred forty-four million, three hundred eighty-one thousand, six hundred forty-three".