643417998 has 8 divisors (see below), whose sum is σ = 1286836008. Its totient is φ = 214472664.

The previous prime is 643417997. The next prime is 643418003. The reversal of 643417998 is 899714346.

It is a sphenic number, since it is the product of 3 distinct primes.

643417998 is an admirable number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 643417998.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643417997) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53618161 + ... + 53618172.

It is an arithmetic number, because the mean of its divisors is an integer number (160854501).

Almost surely, 2^643417998 is an apocalyptic number.

643417998 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

643417998 is a wasteful number, since it uses less digits than its factorization.

643417998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107236338.

The product of its digits is 1306368, while the sum is 51.

The square root of 643417998 is about 25365.6854431336. The cubic root of 643417998 is about 863.3052891447.

The spelling of 643417998 in words is "six hundred forty-three million, four hundred seventeen thousand, nine hundred ninety-eight".