6440324256 has 168 divisors, whose sum is σ = 19372791060. Its totient is φ = 2105865216.

The previous prime is 6440324237. The next prime is 6440324257. The reversal of 6440324256 is 6524230446.

6440324256 is a `hidden beast` number, since 6 + 4 + 403 + 242 + 5 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 5282963856 + 1157360400 = 72684^2 + 34020^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 6440324256.

It is not an unprimeable number, because it can be changed into a prime (6440324257) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 1233780 + ... + 1238988.

Almost surely, 2^6440324256 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 6440324256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9686395530).

6440324256 is an abundant number, since it is smaller than the sum of its proper divisors (12932466804).

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

6440324256 is an equidigital number, since it uses as much as digits as its factorization.

6440324256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5290 (or 5267 counting only the distinct ones).

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

The square root of 6440324256 is about 80251.6308619333. The cubic root of 6440324256 is about 1860.5267186746.

The spelling of 6440324256 in words is "six billion, four hundred forty million, three hundred twenty-four thousand, two hundred fifty-six".