638829899 has 4 divisors (see below), whose sum is σ = 666605136. Its totient is φ = 611054664.

The previous prime is 638829817. The next prime is 638829923. The reversal of 638829899 is 998928836.

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

It is a cyclic number.

It is not a de Polignac number, because 638829899 - 2²⁰ = 637781323 is a prime.

It is not an unprimeable number, because it can be changed into a prime (638829599) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13887584 + ... + 13887629.

It is an arithmetic number, because the mean of its divisors is an integer number (166651284).

Almost surely, 2^638829899 is an apocalyptic number.

638829899 is a deficient number, since it is larger than the sum of its proper divisors (27775237).

638829899 is a wasteful number, since it uses less digits than its factorization.

638829899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27775236.

The product of its digits is 13436928, while the sum is 62.

The square root of 638829899 is about 25275.0845498091. The cubic root of 638829899 is about 861.2483668341.

The spelling of 638829899 in words is "six hundred thirty-eight million, eight hundred twenty-nine thousand, eight hundred ninety-nine".