643081018 has 16 divisors (see below), whose sum is σ = 971502336. Its totient is φ = 319253760.

The previous prime is 643081007. The next prime is 643081027. The reversal of 643081018 is 810180346.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 246903 + ... + 249493.

It is an arithmetic number, because the mean of its divisors is an integer number (60718896).

Almost surely, 2^643081018 is an apocalyptic number.

643081018 is a deficient number, since it is larger than the sum of its proper divisors (328421318).

643081018 is a wasteful number, since it uses less digits than its factorization.

643081018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3429.

The product of its (nonzero) digits is 4608, while the sum is 31.

The square root of 643081018 is about 25359.0421349072. The cubic root of 643081018 is about 863.1545486620.

The spelling of 643081018 in words is "six hundred forty-three million, eighty-one thousand, eighteen".