638684033899 has 4 divisors (see below), whose sum is σ = 639761073336. Its totient is φ = 637606994464.

The previous prime is 638684033887. The next prime is 638684033921. The reversal of 638684033899 is 998330486836.

It is a happy number.

638684033899 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638684033899 is a prime.

It is a super-2 number, since 2×638684033899² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638684033809) 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, 538518829 + ... + 538520014.

It is an arithmetic number, because the mean of its divisors is an integer number (159940268334).

Almost surely, 2^638684033899 is an apocalyptic number.

638684033899 is a deficient number, since it is larger than the sum of its proper divisors (1077039437).

638684033899 is a wasteful number, since it uses less digits than its factorization.

638684033899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1077039436.

The product of its (nonzero) digits is 161243136, while the sum is 67.

The spelling of 638684033899 in words is "six hundred thirty-eight billion, six hundred eighty-four million, thirty-three thousand, eight hundred ninety-nine".