643938 has 8 divisors (see below), whose sum is σ = 1287888. Its totient is φ = 214644.

The previous prime is 643927. The next prime is 643949. The reversal of 643938 is 839346.

643938 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (643927) and next prime (643949).

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

643938 is an admirable number.

It is a super-2 number, since 2×643938² = 829312295688, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 643899 and 643908.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53656 + ... + 53667.

It is an arithmetic number, because the mean of its divisors is an integer number (160986).

2⁶⁴³⁹³⁸ is an apocalyptic number.

643938 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.

643938 is a wasteful number, since it uses less digits than its factorization.

643938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107328.

The product of its digits is 15552, while the sum is 33.

The square root of 643938 is about 802.4574755088. The cubic root of 643938 is about 86.3537797196.

The spelling of 643938 in words is "six hundred forty-three thousand, nine hundred thirty-eight".