638375422178 has 30 divisors (see below), whose sum is σ = 1037667667239. Its totient is φ = 294546675384.

The previous prime is 638375422133. The next prime is 638375422183. The reversal of 638375422178 is 871224573836.

It can be written as a sum of positive squares in 3 ways, for example, as 11175649 + 638364246529 = 3343^2 + 798977^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=564967.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 190957175 + ... + 190960517.

Almost surely, 2^638375422178 is an apocalyptic number.

638375422178 is a deficient number, since it is larger than the sum of its proper divisors (399292245061).

638375422178 is an frugal number, since it uses more digits than its factorization.

638375422178 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6740 (or 3358 counting only the distinct ones).

The product of its digits is 13547520, while the sum is 56.

The spelling of 638375422178 in words is "six hundred thirty-eight billion, three hundred seventy-five million, four hundred twenty-two thousand, one hundred seventy-eight".