6465640320 has 320 divisors, whose sum is σ = 23246403840. Its totient is φ = 1712517120.

The previous prime is 6465640297. The next prime is 6465640327. The reversal of 6465640320 is 230465646.

6465640320 is a `hidden beast` number, since 6 + 4 + 6 + 5 + 640 + 3 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (320).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6465640327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 9901114 + ... + 9901766.

It is an arithmetic number, because the mean of its divisors is an integer number (72645012).

Almost surely, 2^6465640320 is an apocalyptic number.

6465640320 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 6465640320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11623201920).

6465640320 is an abundant number, since it is smaller than the sum of its proper divisors (16780763520).

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

6465640320 is a wasteful number, since it uses less digits than its factorization.

6465640320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 875 (or 854 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 36.

The square root of 6465640320 is about 80409.2054431581. The cubic root of 6465640320 is about 1862.9613596348.

It can be divided in two parts, 64656 and 40320, that added together give a 4-th power (104976 = 18⁴).

The spelling of 6465640320 in words is "six billion, four hundred sixty-five million, six hundred forty thousand, three hundred twenty".