638999822 has 4 divisors (see below), whose sum is σ = 958499736. Its totient is φ = 319499910.

The previous prime is 638999813. The next prime is 638999839. The reversal of 638999822 is 228999836.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 159749954 + ... + 159749957.

It is an arithmetic number, because the mean of its divisors is an integer number (239624934).

Almost surely, 2^638999822 is an apocalyptic number.

638999822 is a deficient number, since it is larger than the sum of its proper divisors (319499914).

638999822 is a wasteful number, since it uses less digits than its factorization.

638999822 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319499913.

The product of its digits is 3359232, while the sum is 56.

The square root of 638999822 is about 25278.4457987432. The cubic root of 638999822 is about 861.3247215011.

The spelling of 638999822 in words is "six hundred thirty-eight million, nine hundred ninety-nine thousand, eight hundred twenty-two".