638422 has 4 divisors (see below), whose sum is σ = 957636. Its totient is φ = 319210.

The previous prime is 638371. The next prime is 638423. The reversal of 638422 is 224836.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638423) 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 as a sum of consecutive naturals, namely, 159604 + ... + 159607.

It is an arithmetic number, because the mean of its divisors is an integer number (239409).

2⁶³⁸⁴²² is an apocalyptic number.

638422 is a deficient number, since it is larger than the sum of its proper divisors (319214).

638422 is a wasteful number, since it uses less digits than its factorization.

638422 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 319213.

The product of its digits is 2304, while the sum is 25.

The square root of 638422 is about 799.0131413187. The cubic root of 638422 is about 86.1065022700.

The spelling of 638422 in words is "six hundred thirty-eight thousand, four hundred twenty-two".