643053636 has 36 divisors (see below), whose sum is σ = 1669432492. Its totient is φ = 208557504.

The previous prime is 643053623. The next prime is 643053637. The reversal of 643053636 is 636350346.

It is a happy number.

643053636 is a `hidden beast` number, since 64 + 30 + 536 + 36 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 350438400 + 292615236 = 18720^2 + 17106^2 .

It is a tau number, because it is divible by the number of its divisors (36).

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 643053636.

It is not an unprimeable number, because it can be changed into a prime (643053637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 240055 + ... + 242718.

Almost surely, 2^643053636 is an apocalyptic number.

It is an amenable number.

643053636 is an abundant number, since it is smaller than the sum of its proper divisors (1026378856).

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

643053636 is a wasteful number, since it uses less digits than its factorization.

643053636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 482820 (or 482815 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 36.

The square root of 643053636 is about 25358.5022428376. The cubic root of 643053636 is about 863.1422976222.

The spelling of 643053636 in words is "six hundred forty-three million, fifty-three thousand, six hundred thirty-six".