643208 has 32 divisors (see below), whose sum is σ = 1292760. Its totient is φ = 299520.

The previous prime is 643199. The next prime is 643213. The reversal of 643208 is 802346.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 574564 + 68644 = 758^2 + 262^2 .

It is an Ulam number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12110 + ... + 12162.

643208 is a Friedman number, since it can be written as 802^(6/3)+4, using all its digits and the basic arithmetic operations.

2⁶⁴³²⁰⁸ is an apocalyptic number.

It is an amenable number.

643208 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.

643208 is a wasteful number, since it uses less digits than its factorization.

643208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137 (or 133 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 643208 is about 802.0024937617. The cubic root of 643208 is about 86.3211357407.

The spelling of 643208 in words is "six hundred forty-three thousand, two hundred eight".