638894792665 has 8 divisors (see below), whose sum is σ = 771377272128. Its totient is φ = 507980153520.

The previous prime is 638894792663. The next prime is 638894792677. The reversal of 638894792665 is 566297498836.

638894792665 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 638894792665 - 2¹ = 638894792663 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638894792663) 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, 391959181 + ... + 391960810.

It is an arithmetic number, because the mean of its divisors is an integer number (96422159016).

Almost surely, 2^638894792665 is an apocalyptic number.

It is an amenable number.

638894792665 is a deficient number, since it is larger than the sum of its proper divisors (132482479463).

638894792665 is a wasteful number, since it uses less digits than its factorization.

638894792665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 783920159.

The product of its digits is 940584960, while the sum is 73.

The spelling of 638894792665 in words is "six hundred thirty-eight billion, eight hundred ninety-four million, seven hundred ninety-two thousand, six hundred sixty-five".