643880 has 16 divisors (see below), whose sum is σ = 1448820. Its totient is φ = 257536.

The previous prime is 643879. The next prime is 643883. The reversal of 643880 is 88346.

It can be written as a sum of positive squares in 2 ways, for example, as 643204 + 676 = 802^2 + 26^2 .

It is not an unprimeable number, because it can be changed into a prime (643883) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8009 + ... + 8088.

2⁶⁴³⁸⁸⁰ is an apocalyptic number.

It is an amenable number.

643880 is an abundant number, since it is smaller than the sum of its proper divisors (804940).

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

643880 is a wasteful number, since it uses less digits than its factorization.

643880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16108 (or 16104 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 643880 is about 802.4213357084. The cubic root of 643880 is about 86.3511869909.

The spelling of 643880 in words is "six hundred forty-three thousand, eight hundred eighty".