638657218882 has 8 divisors (see below), whose sum is σ = 963278568252. Its totient is φ = 317564362800.

The previous prime is 638657218867. The next prime is 638657218919. The reversal of 638657218882 is 288812756836.

638657218882 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 2 ways, for example, as 421630747561 + 217026471321 = 649331^2 + 465861^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 882122869 + ... + 882123592.

Almost surely, 2^638657218882 is an apocalyptic number.

638657218882 is a deficient number, since it is larger than the sum of its proper divisors (324621349370).

638657218882 is a wasteful number, since it uses less digits than its factorization.

638657218882 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1764246644.

The product of its digits is 61931520, while the sum is 64.

The spelling of 638657218882 in words is "six hundred thirty-eight billion, six hundred fifty-seven million, two hundred eighteen thousand, eight hundred eighty-two".