643158906 has 24 divisors (see below), whose sum is σ = 1392878880. Its totient is φ = 197894736.

The previous prime is 643158899. The next prime is 643158907. The reversal of 643158906 is 609851346.

It is not an unprimeable number, because it can be changed into a prime (643158907) 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 11 ways as a sum of consecutive naturals, for example, 316126 + ... + 318153.

It is an arithmetic number, because the mean of its divisors is an integer number (58036620).

Almost surely, 2^643158906 is an apocalyptic number.

643158906 is an abundant number, since it is smaller than the sum of its proper divisors (749719974).

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

643158906 is a wasteful number, since it uses less digits than its factorization.

643158906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 634310 (or 634297 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 42.

The square root of 643158906 is about 25360.5777931024. The cubic root of 643158906 is about 863.1893947988.

The spelling of 643158906 in words is "six hundred forty-three million, one hundred fifty-eight thousand, nine hundred six".