643256460 has 144 divisors (see below), whose sum is σ = 2432731392. Its totient is φ = 133660800.

The previous prime is 643256447. The next prime is 643256461. The reversal of 643256460 is 64652346.

643256460 is a `hidden beast` number, since 6 + 4 + 3 + 2 + 5 + 646 + 0 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (643256461) 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 47 ways as a sum of consecutive naturals, for example, 9346 + ... + 37065.

It is an arithmetic number, because the mean of its divisors is an integer number (16893968).

Almost surely, 2^643256460 is an apocalyptic number.

643256460 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 643256460, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1216365696).

643256460 is an abundant number, since it is smaller than the sum of its proper divisors (1789474932).

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

643256460 is a wasteful number, since it uses less digits than its factorization.

643256460 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46444 (or 46439 counting only the distinct ones).

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

The square root of 643256460 is about 25362.5010596353. The cubic root of 643256460 is about 863.2330352949.

The spelling of 643256460 in words is "six hundred forty-three million, two hundred fifty-six thousand, four hundred sixty".