639825665165 has 8 divisors (see below), whose sum is σ = 788541901080. Its totient is φ = 498026463552.

The previous prime is 639825665153. The next prime is 639825665207. The reversal of 639825665165 is 561566528936.

639825665165 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 113055992644 + 526769672521 = 336238^2 + 725789^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 639825665165 - 2¹⁶ = 639825599629 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 639825665098 and 639825665107.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1729258370 + ... + 1729258739.

It is an arithmetic number, because the mean of its divisors is an integer number (98567737635).

Almost surely, 2^639825665165 is an apocalyptic number.

It is an amenable number.

639825665165 is a deficient number, since it is larger than the sum of its proper divisors (148716235915).

639825665165 is a wasteful number, since it uses less digits than its factorization.

639825665165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3458517151.

The product of its digits is 69984000, while the sum is 62.

The spelling of 639825665165 in words is "six hundred thirty-nine billion, eight hundred twenty-five million, six hundred sixty-five thousand, one hundred sixty-five".