643542636 has 24 divisors (see below), whose sum is σ = 1638108864. Its totient is φ = 195012880.

The previous prime is 643542629. The next prime is 643542637. The reversal of 643542636 is 636245346.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 643542594 and 643542603.

It is not an unprimeable number, because it can be changed into a prime (643542637) 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 7 ways as a sum of consecutive naturals, for example, 2437530 + ... + 2437793.

It is an arithmetic number, because the mean of its divisors is an integer number (68254536).

Almost surely, 2^643542636 is an apocalyptic number.

643542636 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

643542636 is an abundant number, since it is smaller than the sum of its proper divisors (994566228).

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

643542636 is a wasteful number, since it uses less digits than its factorization.

643542636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4875341 (or 4875339 counting only the distinct ones).

The product of its digits is 311040, while the sum is 39.

The square root of 643542636 is about 25368.1421471893. The cubic root of 643542636 is about 863.3610298388.

The spelling of 643542636 in words is "six hundred forty-three million, five hundred forty-two thousand, six hundred thirty-six".