643670 has 16 divisors (see below), whose sum is σ = 1168128. Its totient is φ = 255360.

The previous prime is 643661. The next prime is 643681. The reversal of 643670 is 76346.

643670 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×643670² = 828622137800, which contains 22 as substring.

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 643670.

It is an unprimeable number.

643670 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 in 7 ways as a sum of consecutive naturals, for example, 1742 + ... + 2078.

It is an arithmetic number, because the mean of its divisors is an integer number (73008).

2⁶⁴³⁶⁷⁰ is an apocalyptic number.

643670 is a deficient number, since it is larger than the sum of its proper divisors (524458).

643670 is a wasteful number, since it uses less digits than its factorization.

643670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 535.

The product of its (nonzero) digits is 3024, while the sum is 26.

The square root of 643670 is about 802.2904710889. The cubic root of 643670 is about 86.3417982222.

The spelling of 643670 in words is "six hundred forty-three thousand, six hundred seventy".