639870713 has 4 divisors (see below), whose sum is σ = 641207040. Its totient is φ = 638534388.

The previous prime is 639870689. The next prime is 639870727. The reversal of 639870713 is 317078936.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 639870713 - 2²⁰ = 638822137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639870773) 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, 667445 + ... + 668402.

It is an arithmetic number, because the mean of its divisors is an integer number (160301760).

Almost surely, 2^639870713 is an apocalyptic number.

It is an amenable number.

639870713 is a deficient number, since it is larger than the sum of its proper divisors (1336327).

639870713 is a wasteful number, since it uses less digits than its factorization.

639870713 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1336326.

The product of its (nonzero) digits is 190512, while the sum is 44.

The square root of 639870713 is about 25295.6658935874. The cubic root of 639870713 is about 861.7158428553.

The spelling of 639870713 in words is "six hundred thirty-nine million, eight hundred seventy thousand, seven hundred thirteen".