643969152 has 48 divisors (see below), whose sum is σ = 1853091630. Its totient is φ = 214656000.

The previous prime is 643969141. The next prime is 643969159. The reversal of 643969152 is 251969346.

643969152 is a `hidden beast` number, since 6 + 439 + 69 + 152 = 666.

It can be written as a sum of positive squares in only one way, i.e., 531948096 + 112021056 = 23064^2 + 10584^2 .

It is a tau number, because it is divible by the number of its divisors (48).

It is a junction number, because it is equal to n+sod(n) for n = 643969098 and 643969107.

It is not an unprimeable number, because it can be changed into a prime (643969159) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 278349 + ... + 280652.

Almost surely, 2^643969152 is an apocalyptic number.

It is an amenable number.

643969152 is an abundant number, since it is smaller than the sum of its proper divisors (1209122478).

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

643969152 is a wasteful number, since it uses less digits than its factorization.

643969152 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 559021 (or 559006 counting only the distinct ones).

The product of its digits is 349920, while the sum is 45.

The square root of 643969152 is about 25376.5472828752. The cubic root of 643969152 is about 863.5517221882.

The spelling of 643969152 in words is "six hundred forty-three million, nine hundred sixty-nine thousand, one hundred fifty-two".