643628 has 6 divisors (see below), whose sum is σ = 1126356. Its totient is φ = 321812.

The previous prime is 643619. The next prime is 643633. The reversal of 643628 is 826346.

It is a nialpdrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 643628.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 643628.

It is an unprimeable number.

643628 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80450 + ... + 80457.

It is an arithmetic number, because the mean of its divisors is an integer number (187726).

2⁶⁴³⁶²⁸ is an apocalyptic number.

It is an amenable number.

643628 is a deficient number, since it is larger than the sum of its proper divisors (482728).

643628 is a wasteful number, since it uses less digits than its factorization.

643628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160911 (or 160909 counting only the distinct ones).

The product of its digits is 6912, while the sum is 29.

The square root of 643628 is about 802.2642956034. The cubic root of 643628 is about 86.3399202235.

It can be divided in two parts, 6 and 43628, that added together give a palindrome (43634).

The spelling of 643628 in words is "six hundred forty-three thousand, six hundred twenty-eight".