639488071 has 4 divisors (see below), whose sum is σ = 649971544. Its totient is φ = 629004600.

The previous prime is 639488041. The next prime is 639488081. The reversal of 639488071 is 170884936.

It is a happy number.

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 639488071 - 2⁷ = 639487943 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 (639488041) 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, 5241645 + ... + 5241766.

It is an arithmetic number, because the mean of its divisors is an integer number (162492886).

Almost surely, 2^639488071 is an apocalyptic number.

639488071 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

639488071 is a deficient number, since it is larger than the sum of its proper divisors (10483473).

639488071 is a wasteful number, since it uses less digits than its factorization.

639488071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10483472.

The product of its (nonzero) digits is 290304, while the sum is 46.

The square root of 639488071 is about 25288.1013719892. The cubic root of 639488071 is about 861.5440402216.

The spelling of 639488071 in words is "six hundred thirty-nine million, four hundred eighty-eight thousand, seventy-one".