645754320 has 120 divisors (see below), whose sum is σ = 2188125576. Its totient is φ = 170655744.

The previous prime is 645754289. The next prime is 645754321. The reversal of 645754320 is 23457546.

645754320 is a `hidden beast` number, since 64 + 57 + 543 + 2 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 73205136 + 572549184 = 8556^2 + 23928^2 .

It is a tau number, because it is divible by the number of its divisors (120).

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 (645754321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 77392 + ... + 85328.

Almost surely, 2^645754320 is an apocalyptic number.

645754320 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 645754320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1094062788).

645754320 is an abundant number, since it is smaller than the sum of its proper divisors (1542371256).

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

645754320 is a wasteful number, since it uses less digits than its factorization.

645754320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8069 (or 8060 counting only the distinct ones).

The product of its (nonzero) digits is 100800, while the sum is 36.

The square root of 645754320 is about 25411.6965195164. The cubic root of 645754320 is about 864.3489459854.

The spelling of 645754320 in words is "six hundred forty-five million, seven hundred fifty-four thousand, three hundred twenty".