638725 has 12 divisors (see below), whose sum is σ = 820260. Its totient is φ = 492800.

The previous prime is 638719. The next prime is 638767. The reversal of 638725 is 527836.

It can be written as a sum of positive squares in 6 ways, for example, as 58081 + 580644 = 241^2 + 762^2 .

It is not a de Polignac number, because 638725 - 2³ = 638717 is a prime.

It is an alternating number because its digits alternate between even and odd.

638725 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 11 ways as a sum of consecutive naturals, for example, 285 + ... + 1165.

It is an arithmetic number, because the mean of its divisors is an integer number (68355).

2⁶³⁸⁷²⁵ is an apocalyptic number.

It is an amenable number.

638725 is a deficient number, since it is larger than the sum of its proper divisors (181535).

638725 is a wasteful number, since it uses less digits than its factorization.

638725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 920 (or 915 counting only the distinct ones).

The product of its digits is 10080, while the sum is 31.

The square root of 638725 is about 799.2027277231. The cubic root of 638725 is about 86.1201223853.

Subtracting from 638725 its reverse (527836), we obtain a square (110889 = 333²).

The spelling of 638725 in words is "six hundred thirty-eight thousand, seven hundred twenty-five".