638730271 has 4 divisors (see below), whose sum is σ = 647726544. Its totient is φ = 629734000.

The previous prime is 638730199. The next prime is 638730289. The reversal of 638730271 is 172037836.

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-638730271 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 638730271.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638730571) 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 3 ways as a sum of consecutive naturals, for example, 4498030 + ... + 4498171.

It is an arithmetic number, because the mean of its divisors is an integer number (161931636).

Almost surely, 2^638730271 is an apocalyptic number.

638730271 is a deficient number, since it is larger than the sum of its proper divisors (8996273).

638730271 is an equidigital number, since it uses as much as digits as its factorization.

638730271 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8996272.

The product of its (nonzero) digits is 42336, while the sum is 37.

The square root of 638730271 is about 25273.1135992382. The cubic root of 638730271 is about 861.2035928323.

The spelling of 638730271 in words is "six hundred thirty-eight million, seven hundred thirty thousand, two hundred seventy-one".