638771 has 4 divisors (see below), whose sum is σ = 730032. Its totient is φ = 547512.

The previous prime is 638767. The next prime is 638801. The reversal of 638771 is 177836.

It is a happy number.

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

It is not a de Polignac number, because 638771 - 2² = 638767 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 (638171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45620 + ... + 45633.

It is an arithmetic number, because the mean of its divisors is an integer number (182508).

2⁶³⁸⁷⁷¹ is an apocalyptic number.

638771 is a deficient number, since it is larger than the sum of its proper divisors (91261).

638771 is an equidigital number, since it uses as much as digits as its factorization.

638771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91260.

The product of its digits is 7056, while the sum is 32.

The square root of 638771 is about 799.2315058855. The cubic root of 638771 is about 86.1221897489.

The spelling of 638771 in words is "six hundred thirty-eight thousand, seven hundred seventy-one".