638405136281 has 8 divisors (see below), whose sum is σ = 701758319328. Its totient is φ = 575938012000.

The previous prime is 638405136269. The next prime is 638405136331. The reversal of 638405136281 is 182631504836.

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 638405136281 - 2¹⁸ = 638404874137 is a prime.

It is a super-3 number, since 3×638405136281³ (a number of 36 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (638405136181) 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, 221513180 + ... + 221516061.

It is an arithmetic number, because the mean of its divisors is an integer number (87719789916).

Almost surely, 2^638405136281 is an apocalyptic number.

It is an amenable number.

638405136281 is a deficient number, since it is larger than the sum of its proper divisors (63353183047).

638405136281 is a wasteful number, since it uses less digits than its factorization.

638405136281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 443029383.

The product of its (nonzero) digits is 829440, while the sum is 47.

The spelling of 638405136281 in words is "six hundred thirty-eight billion, four hundred five million, one hundred thirty-six thousand, two hundred eighty-one".