643155 has 16 divisors (see below), whose sum is σ = 1049760. Its totient is φ = 336128.

The previous prime is 643129. The next prime is 643183. The reversal of 643155 is 551346.

643155 is digitally balanced in base 7, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 643155 - 2⁸ = 642899 is a prime.

643155 is strictly pandigital in base 7.

643155 is a lucky number.

It is a nialpdrome in base 15.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 391 + ... + 1199.

It is an arithmetic number, because the mean of its divisors is an integer number (65610).

2⁶⁴³¹⁵⁵ is an apocalyptic number.

643155 is a deficient number, since it is larger than the sum of its proper divisors (406605).

643155 is a wasteful number, since it uses less digits than its factorization.

643155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 870.

The product of its digits is 1800, while the sum is 24.

The square root of 643155 is about 801.9694507897. The cubic root of 643155 is about 86.3187647369.

Subtracting from 643155 its reverse (551346), we obtain a square (91809 = 303²).

The spelling of 643155 in words is "six hundred forty-three thousand, one hundred fifty-five".