638785883665 has 8 divisors (see below), whose sum is σ = 768067005888. Its totient is φ = 510012743280.

The previous prime is 638785883663. The next prime is 638785883669. The reversal of 638785883665 is 566388587836.

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

It is not a de Polignac number, because 638785883665 - 2¹ = 638785883663 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638785883663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126992691 + ... + 126997720.

It is an arithmetic number, because the mean of its divisors is an integer number (96008375736).

Almost surely, 2^638785883665 is an apocalyptic number.

It is an amenable number.

638785883665 is a deficient number, since it is larger than the sum of its proper divisors (129281122223).

638785883665 is a wasteful number, since it uses less digits than its factorization.

638785883665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253990919.

The product of its digits is 1393459200, while the sum is 73.

The spelling of 638785883665 in words is "six hundred thirty-eight billion, seven hundred eighty-five million, eight hundred eighty-three thousand, six hundred sixty-five".