638838137144 has 8 divisors (see below), whose sum is σ = 1197821507160. Its totient is φ = 319419068568.

The previous prime is 638838137143. The next prime is 638838137219. The reversal of 638838137144 is 441731838836.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×638838137144² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 638838137144.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638838137141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39927383564 + ... + 39927383579.

It is an arithmetic number, because the mean of its divisors is an integer number (149727688395).

Almost surely, 2^638838137144 is an apocalyptic number.

It is an amenable number.

638838137144 is a deficient number, since it is larger than the sum of its proper divisors (558983370016).

638838137144 is a wasteful number, since it uses less digits than its factorization.

638838137144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79854767149 (or 79854767145 counting only the distinct ones).

The product of its digits is 9289728, while the sum is 56.

The spelling of 638838137144 in words is "six hundred thirty-eight billion, eight hundred thirty-eight million, one hundred thirty-seven thousand, one hundred forty-four".