643125 has 40 divisors (see below), whose sum is σ = 1249600. Its totient is φ = 294000.

The previous prime is 643121. The next prime is 643129. The reversal of 643125 is 521346.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (643121) and next prime (643129).

It is not a de Polignac number, because 643125 - 2² = 643121 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

Its product of digits (720) is a multiple of the sum of its prime divisors (15).

It is a nialpdrome in base 15.

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 643125.

It is not an unprimeable number, because it can be changed into a prime (643121) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 91872 + ... + 91878.

It is an arithmetic number, because the mean of its divisors is an integer number (31240).

2⁶⁴³¹²⁵ is an apocalyptic number.

It is an amenable number.

643125 is a deficient number, since it is larger than the sum of its proper divisors (606475).

643125 is an frugal number, since it uses more digits than its factorization.

643125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44 (or 15 counting only the distinct ones).

The product of its digits is 720, while the sum is 21.

The square root of 643125 is about 801.9507466173. The cubic root of 643125 is about 86.3174226016.

Multiplying 643125 by its sum of digits (21), we get a square (13505625 = 3675²).

643125 divided by its sum of digits (21) gives a square (30625 = 175²).

The spelling of 643125 in words is "six hundred forty-three thousand, one hundred twenty-five".