638627236745 has 4 divisors (see below), whose sum is σ = 766352684100. Its totient is φ = 510901789392.

The previous prime is 638627236739. The next prime is 638627236811. The reversal of 638627236745 is 547632726836.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 497584927609 + 141042309136 = 705397^2 + 375556^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638627236745 is a prime.

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 3 ways as a sum of consecutive naturals, for example, 63862723670 + ... + 63862723679.

It is an arithmetic number, because the mean of its divisors is an integer number (191588171025).

Almost surely, 2^638627236745 is an apocalyptic number.

It is an amenable number.

638627236745 is a deficient number, since it is larger than the sum of its proper divisors (127725447355).

638627236745 is a wasteful number, since it uses less digits than its factorization.

638627236745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127725447354.

The product of its digits is 60963840, while the sum is 59.

The spelling of 638627236745 in words is "six hundred thirty-eight billion, six hundred twenty-seven million, two hundred thirty-six thousand, seven hundred forty-five".