639714191 has 4 divisors (see below), whose sum is σ = 649262232. Its totient is φ = 630166152.

The previous prime is 639714181. The next prime is 639714193. The reversal of 639714191 is 191417936.

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-639714191 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 (639714193) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4773920 + ... + 4774053.

It is an arithmetic number, because the mean of its divisors is an integer number (162315558).

Almost surely, 2^639714191 is an apocalyptic number.

639714191 is a deficient number, since it is larger than the sum of its proper divisors (9548041).

639714191 is an equidigital number, since it uses as much as digits as its factorization.

639714191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9548040.

The product of its digits is 40824, while the sum is 41.

The square root of 639714191 is about 25292.5718542026. The cubic root of 639714191 is about 861.6455742403.

The spelling of 639714191 in words is "six hundred thirty-nine million, seven hundred fourteen thousand, one hundred ninety-one".