643128 has 32 divisors (see below), whose sum is σ = 1628160. Its totient is φ = 211680.

The previous prime is 643121. The next prime is 643129. The reversal of 643128 is 821346.

It is a happy number.

It is a super-2 number, since 2×643128² = 827227248768, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a nude number because it is divisible by every one of its digits.

It is an Ulam number.

It is one of the 548 Lynch-Bell numbers.

It is a nialpdrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 643098 and 643107.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 643128.

It is not an unprimeable number, because it can be changed into a prime (643121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2943 + ... + 3153.

It is an arithmetic number, because the mean of its divisors is an integer number (50880).

2⁶⁴³¹²⁸ is an apocalyptic number.

It is an amenable number.

643128 is an abundant number, since it is smaller than the sum of its proper divisors (985032).

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

643128 is a wasteful number, since it uses less digits than its factorization.

643128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 347 (or 343 counting only the distinct ones).

The product of its digits is 1152, while the sum is 24.

The square root of 643128 is about 801.9526170541. The cubic root of 643128 is about 86.3175568170.

It can be divided in two parts, 6 and 43128, that added together give a palindrome (43134).

The spelling of 643128 in words is "six hundred forty-three thousand, one hundred twenty-eight".