638840760221 has 8 divisors (see below), whose sum is σ = 667133634240. Its totient is φ = 610590985312.

The previous prime is 638840760169. The next prime is 638840760223. The reversal of 638840760221 is 122067048836.

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

It is not a de Polignac number, because 638840760221 - 2¹⁰ = 638840759197 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638840760223) 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, 10744475 + ... + 10803768.

It is an arithmetic number, because the mean of its divisors is an integer number (83391704280).

Almost surely, 2^638840760221 is an apocalyptic number.

It is an amenable number.

638840760221 is a deficient number, since it is larger than the sum of its proper divisors (28292874019).

638840760221 is a wasteful number, since it uses less digits than its factorization.

638840760221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21549555.

The product of its (nonzero) digits is 774144, while the sum is 47.

The spelling of 638840760221 in words is "six hundred thirty-eight billion, eight hundred forty million, seven hundred sixty thousand, two hundred twenty-one".