6443252640 has 576 divisors, whose sum is σ = 25662873600. Its totient is φ = 1455667200.

The previous prime is 6443252639. The next prime is 6443252657. The reversal of 6443252640 is 462523446.

6443252640 is a `hidden beast` number, since 6 + 4 + 4 + 3 + 2 + 5 + 2 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 6443252595 and 6443252604.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 23775705 + ... + 23775975.

It is an arithmetic number, because the mean of its divisors is an integer number (44553600).

Almost surely, 2^6443252640 is an apocalyptic number.

6443252640 is a gapful number since it is divisible by the number (60) 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 6443252640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12831436800).

6443252640 is an abundant number, since it is smaller than the sum of its proper divisors (19219620960).

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

6443252640 is a wasteful number, since it uses less digits than its factorization.

6443252640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 401 (or 390 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 36.

The square root of 6443252640 is about 80269.8738008227. The cubic root of 6443252640 is about 1860.8086667510.

The spelling of 6443252640 in words is "six billion, four hundred forty-three million, two hundred fifty-two thousand, six hundred forty".