638711 has 4 divisors (see below), whose sum is σ = 648312. Its totient is φ = 629112.

The previous prime is 638699. The next prime is 638717. The reversal of 638711 is 117836.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638711 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638717) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4700 + ... + 4833.

It is an arithmetic number, because the mean of its divisors is an integer number (162078).

2⁶³⁸⁷¹¹ is an apocalyptic number.

638711 is a deficient number, since it is larger than the sum of its proper divisors (9601).

638711 is an equidigital number, since it uses as much as digits as its factorization.

638711 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9600.

The product of its digits is 1008, while the sum is 26.

The square root of 638711 is about 799.1939689462. The cubic root of 638711 is about 86.1194931680.

The spelling of 638711 in words is "six hundred thirty-eight thousand, seven hundred eleven".