638822 has 4 divisors (see below), whose sum is σ = 958236. Its totient is φ = 319410.

The previous prime is 638819. The next prime is 638839. The reversal of 638822 is 228836.

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

It is an Ulam number.

It is a nialpdrome in base 15.

It is a congruent number.

It is an unprimeable number.

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, 159704 + ... + 159707.

It is an arithmetic number, because the mean of its divisors is an integer number (239559).

2⁶³⁸⁸²² is an apocalyptic number.

638822 is a deficient number, since it is larger than the sum of its proper divisors (319414).

638822 is a wasteful number, since it uses less digits than its factorization.

638822 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 319413.

The product of its digits is 4608, while the sum is 29.

The square root of 638822 is about 799.2634108978. The cubic root of 638822 is about 86.1244817100.

The spelling of 638822 in words is "six hundred thirty-eight thousand, eight hundred twenty-two".