638731607281 has 8 divisors (see below), whose sum is σ = 684516129984. Its totient is φ = 594448216560.

The previous prime is 638731607203. The next prime is 638731607303. The reversal of 638731607281 is 182706137836.

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

It is a cyclic number.

It is not a de Polignac number, because 638731607281 - 2¹⁹ = 638731082993 is a prime.

It is a super-2 number, since 2×638731607281² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638731607681) 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, 375282115 + ... + 375283816.

It is an arithmetic number, because the mean of its divisors is an integer number (85564516248).

Almost surely, 2^638731607281 is an apocalyptic number.

It is an amenable number.

638731607281 is a deficient number, since it is larger than the sum of its proper divisors (45784522703).

638731607281 is a wasteful number, since it uses less digits than its factorization.

638731607281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 750565991.

The product of its (nonzero) digits is 2032128, while the sum is 52.

The spelling of 638731607281 in words is "six hundred thirty-eight billion, seven hundred thirty-one million, six hundred seven thousand, two hundred eighty-one".