638028767 has 4 divisors (see below), whose sum is σ = 638326176. Its totient is φ = 637731360.

The previous prime is 638028761. The next prime is 638028779. The reversal of 638028767 is 767820836.

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 638028767 - 2¹⁶ = 637963231 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638028761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 145463 + ... + 149784.

It is an arithmetic number, because the mean of its divisors is an integer number (159581544).

Almost surely, 2^638028767 is an apocalyptic number.

638028767 is a deficient number, since it is larger than the sum of its proper divisors (297409).

638028767 is a wasteful number, since it uses less digits than its factorization.

638028767 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 297408.

The product of its (nonzero) digits is 677376, while the sum is 47.

The square root of 638028767 is about 25259.2313224294. The cubic root of 638028767 is about 860.8881967524. Note that the first 3 decimals are identical.

The spelling of 638028767 in words is "six hundred thirty-eight million, twenty-eight thousand, seven hundred sixty-seven".