639919023 has 4 divisors (see below), whose sum is σ = 853225368. Its totient is φ = 426612680.

The previous prime is 639919013. The next prime is 639919037. The reversal of 639919023 is 320919936.

It is a happy number.

639919023 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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-639919023 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639919003) 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, 106653168 + ... + 106653173.

It is an arithmetic number, because the mean of its divisors is an integer number (213306342).

Almost surely, 2^639919023 is an apocalyptic number.

639919023 is a deficient number, since it is larger than the sum of its proper divisors (213306345).

639919023 is a wasteful number, since it uses less digits than its factorization.

639919023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213306344.

The product of its (nonzero) digits is 78732, while the sum is 42.

The square root of 639919023 is about 25296.6207822310. The cubic root of 639919023 is about 861.7375287177.

The spelling of 639919023 in words is "six hundred thirty-nine million, nine hundred nineteen thousand, twenty-three".