639711523 has 4 divisors (see below), whose sum is σ = 697867128. Its totient is φ = 581555920.

The previous prime is 639711521. The next prime is 639711529. The reversal of 639711523 is 325117936.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 639711523 - 2¹ = 639711521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639711521) 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, 29077786 + ... + 29077807.

It is an arithmetic number, because the mean of its divisors is an integer number (174466782).

Almost surely, 2^639711523 is an apocalyptic number.

639711523 is a deficient number, since it is larger than the sum of its proper divisors (58155605).

639711523 is a wasteful number, since it uses less digits than its factorization.

639711523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58155604.

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

The square root of 639711523 is about 25292.5191113894. The cubic root of 639711523 is about 861.6443763753.

The spelling of 639711523 in words is "six hundred thirty-nine million, seven hundred eleven thousand, five hundred twenty-three".