638849828 has 12 divisors (see below), whose sum is σ = 1136315292. Its totient is φ = 314188320.

The previous prime is 638849801. The next prime is 638849831. The reversal of 638849828 is 828948836.

It can be written as a sum of positive squares in 2 ways, for example, as 155201764 + 483648064 = 12458^2 + 21992^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1308875 + ... + 1309362.

It is an arithmetic number, because the mean of its divisors is an integer number (94692941).

Almost surely, 2^638849828 is an apocalyptic number.

It is an amenable number.

638849828 is a deficient number, since it is larger than the sum of its proper divisors (497465464).

638849828 is a wasteful number, since it uses less digits than its factorization.

638849828 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2618302 (or 2618300 counting only the distinct ones).

The product of its digits is 5308416, while the sum is 56.

The square root of 638849828 is about 25275.4787887391. The cubic root of 638849828 is about 861.2573226038.

The spelling of 638849828 in words is "six hundred thirty-eight million, eight hundred forty-nine thousand, eight hundred twenty-eight".