638405335845 has 12 divisors (see below), whose sum is σ = 1106569248876. Its totient is φ = 340482845760.

The previous prime is 638405335837. The next prime is 638405335853. The reversal of 638405335845 is 548533504836.

638405335845 is a `hidden beast` number, since 6 + 3 + 8 + 4 + 0 + 53 + 3 + 584 + 5 = 666.

638405335845 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (638405335837) and next prime (638405335853).

It can be written as a sum of positive squares in 2 ways, for example, as 355771689156 + 282633646689 = 596466^2 + 531633^2 .

It is not a de Polignac number, because 638405335845 - 2³ = 638405335837 is a prime.

It is a super-2 number, since 2×638405335845² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 638405335791 and 638405335800.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7093392576 + ... + 7093392665.

It is an arithmetic number, because the mean of its divisors is an integer number (92214104073).

Almost surely, 2^638405335845 is an apocalyptic number.

It is an amenable number.

638405335845 is a deficient number, since it is larger than the sum of its proper divisors (468163913031).

638405335845 is a wasteful number, since it uses less digits than its factorization.

638405335845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14186785252 (or 14186785249 counting only the distinct ones).

The product of its (nonzero) digits is 20736000, while the sum is 54.

The spelling of 638405335845 in words is "six hundred thirty-eight billion, four hundred five million, three hundred thirty-five thousand, eight hundred forty-five".