638849699 has 8 divisors (see below), whose sum is σ = 654360000. Its totient is φ = 623495592.

The previous prime is 638849689. The next prime is 638849723. The reversal of 638849699 is 996948836.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 638849699 - 2⁴ = 638849683 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638849639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30749 + ... + 47150.

It is an arithmetic number, because the mean of its divisors is an integer number (81795000).

Almost surely, 2^638849699 is an apocalyptic number.

638849699 is a deficient number, since it is larger than the sum of its proper divisors (15510301).

638849699 is a wasteful number, since it uses less digits than its factorization.

638849699 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78097.

The product of its digits is 20155392, while the sum is 62.

The square root of 638849699 is about 25275.4762368585. The cubic root of 638849699 is about 861.2572646338.

The spelling of 638849699 in words is "six hundred thirty-eight million, eight hundred forty-nine thousand, six hundred ninety-nine".