639799127881 has 2 divisors, whose sum is σ = 639799127882. Its totient is φ = 639799127880.

The previous prime is 639799127837. The next prime is 639799127911. The reversal of 639799127881 is 188721997936.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 453420423225 + 186378704656 = 673365^2 + 431716^2 .

It is a cyclic number.

It is not a de Polignac number, because 639799127881 - 2²⁵ = 639765573449 is a prime.

It is a super-2 number, since 2×639799127881² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 639799127881.

It is not a weakly prime, because it can be changed into another prime (639799127801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319899563940 + 319899563941.

It is an arithmetic number, because the mean of its divisors is an integer number (319899563941).

Almost surely, 2^639799127881 is an apocalyptic number.

It is an amenable number.

639799127881 is a deficient number, since it is larger than the sum of its proper divisors (1).

639799127881 is an equidigital number, since it uses as much as digits as its factorization.

639799127881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 82301184, while the sum is 70.

The spelling of 639799127881 in words is "six hundred thirty-nine billion, seven hundred ninety-nine million, one hundred twenty-seven thousand, eight hundred eighty-one".