643388 has 12 divisors (see below), whose sum is σ = 1132320. Its totient is φ = 319872.

The previous prime is 643373. The next prime is 643403. The reversal of 643388 is 883346.

643388 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 (643373) and next prime (643403).

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

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, 620 + ... + 1292.

It is an arithmetic number, because the mean of its divisors is an integer number (94360).

2⁶⁴³³⁸⁸ is an apocalyptic number.

It is an amenable number.

643388 is a deficient number, since it is larger than the sum of its proper divisors (488932).

643388 is a wasteful number, since it uses less digits than its factorization.

643388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 916 (or 914 counting only the distinct ones).

The product of its digits is 13824, while the sum is 32.

The square root of 643388 is about 802.1147050142. The cubic root of 643388 is about 86.3291872343.

It can be divided in two parts, 64338 and 8, that added together give a palindrome (64346).

The spelling of 643388 in words is "six hundred forty-three thousand, three hundred eighty-eight".