639799127939 has 4 divisors (see below), whose sum is σ = 655403984760. Its totient is φ = 624194271120.

The previous prime is 639799127911. The next prime is 639799127959. The reversal of 639799127939 is 939721997936.

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-639799127939 is a prime.

It is a super-2 number, since 2×639799127939² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639799127959) 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, 7802428349 + ... + 7802428430.

It is an arithmetic number, because the mean of its divisors is an integer number (163850996190).

Almost surely, 2^639799127939 is an apocalyptic number.

639799127939 is a deficient number, since it is larger than the sum of its proper divisors (15604856821).

639799127939 is a wasteful number, since it uses less digits than its factorization.

639799127939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15604856820.

The product of its digits is 312487308, while the sum is 74.

The spelling of 639799127939 in words is "six hundred thirty-nine billion, seven hundred ninety-nine million, one hundred twenty-seven thousand, nine hundred thirty-nine".