639513271 has 2 divisors, whose sum is σ = 639513272. Its totient is φ = 639513270.

The previous prime is 639513269. The next prime is 639513283. The reversal of 639513271 is 172315936.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 639513271 - 2¹ = 639513269 is a prime.

Together with 639513269, it forms a pair of twin primes.

It is equal to p_33276466 and since 639513271 and 33276466 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 639513271.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639513221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319756635 + 319756636.

It is an arithmetic number, because the mean of its divisors is an integer number (319756636).

Almost surely, 2^639513271 is an apocalyptic number.

639513271 is a deficient number, since it is larger than the sum of its proper divisors (1).

639513271 is an equidigital number, since it uses as much as digits as its factorization.

639513271 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34020, while the sum is 37.

The square root of 639513271 is about 25288.5996251275. The cubic root of 639513271 is about 861.5553568906. Note that the first 3 decimals are identical.

The spelling of 639513271 in words is "six hundred thirty-nine million, five hundred thirteen thousand, two hundred seventy-one".