643925 has 12 divisors (see below), whose sum is σ = 818400. Its totient is φ = 502320.

The previous prime is 643919. The next prime is 643927. The reversal of 643925 is 529346.

It is not a de Polignac number, because 643925 - 2¹⁴ = 627541 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 776 + ... + 1374.

It is an arithmetic number, because the mean of its divisors is an integer number (68200).

2⁶⁴³⁹²⁵ is an apocalyptic number.

It is an amenable number.

643925 is a deficient number, since it is larger than the sum of its proper divisors (174475).

643925 is a wasteful number, since it uses less digits than its factorization.

643925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 652 (or 647 counting only the distinct ones).

The product of its digits is 6480, while the sum is 29.

The square root of 643925 is about 802.4493753502. The cubic root of 643925 is about 86.3531986043.

The spelling of 643925 in words is "six hundred forty-three thousand, nine hundred twenty-five".