639925 has 24 divisors (see below), whose sum is σ = 937440. Its totient is φ = 427200.

The previous prime is 639911. The next prime is 639937. The reversal of 639925 is 529936.

It is a happy number.

It is not a de Polignac number, because 639925 - 2¹³ = 631733 is a prime.

639925 is a lucky number.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 3486 + ... + 3664.

It is an arithmetic number, because the mean of its divisors is an integer number (39060).

2⁶³⁹⁹²⁵ is an apocalyptic number.

639925 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

639925 is a deficient number, since it is larger than the sum of its proper divisors (297515).

639925 is a wasteful number, since it uses less digits than its factorization.

639925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213 (or 208 counting only the distinct ones).

The product of its digits is 14580, while the sum is 34.

The square root of 639925 is about 799.9531236266. The cubic root of 639925 is about 86.1740211656.

The spelling of 639925 in words is "six hundred thirty-nine thousand, nine hundred twenty-five".