639441 has 16 divisors (see below), whose sum is σ = 1033920. Its totient is φ = 387360.

The previous prime is 639439. The next prime is 639451. The reversal of 639441 is 144936.

It is not a de Polignac number, because 639441 - 2¹ = 639439 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

639441 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639451) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 780 + ... + 1373.

It is an arithmetic number, because the mean of its divisors is an integer number (64620).

2⁶³⁹⁴⁴¹ is an apocalyptic number.

It is an amenable number.

639441 is a deficient number, since it is larger than the sum of its proper divisors (394479).

639441 is a wasteful number, since it uses less digits than its factorization.

639441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2173 (or 2167 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 639441 is about 799.6505486774. The cubic root of 639441 is about 86.1522901055.

The spelling of 639441 in words is "six hundred thirty-nine thousand, four hundred forty-one".