643508 has 6 divisors (see below), whose sum is σ = 1126146. Its totient is φ = 321752.

The previous prime is 643507. The next prime is 643523. The reversal of 643508 is 805346.

643508 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 595984 + 47524 = 772^2 + 218^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80435 + ... + 80442.

It is an arithmetic number, because the mean of its divisors is an integer number (187691).

2⁶⁴³⁵⁰⁸ is an apocalyptic number.

It is an amenable number.

643508 is a deficient number, since it is larger than the sum of its proper divisors (482638).

643508 is a wasteful number, since it uses less digits than its factorization.

643508 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160881 (or 160879 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 643508 is about 802.1895037957. The cubic root of 643508 is about 86.3345540625.

The spelling of 643508 in words is "six hundred forty-three thousand, five hundred eight".