643386 has 16 divisors (see below), whose sum is σ = 1296864. Its totient is φ = 212784.

The previous prime is 643373. The next prime is 643403. The reversal of 643386 is 683346.

643386 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is a nialpdrome in base 15.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 601 + ... + 1283.

It is an arithmetic number, because the mean of its divisors is an integer number (81054).

2⁶⁴³³⁸⁶ is an apocalyptic number.

643386 is an abundant number, since it is smaller than the sum of its proper divisors (653478).

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

643386 is a wasteful number, since it uses less digits than its factorization.

643386 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 845.

The product of its digits is 10368, while the sum is 30.

The square root of 643386 is about 802.1134583087. The cubic root of 643386 is about 86.3290977815.

The spelling of 643386 in words is "six hundred forty-three thousand, three hundred eighty-six".