638644124160 has 2240 divisors, whose sum is σ = 2885335326720. Its totient is φ = 132219371520.

The previous prime is 638644124143. The next prime is 638644124161. The reversal of 638644124160 is 61421446836.

638644124160 is a `hidden beast` number, since 63 + 86 + 4 + 412 + 41 + 60 = 666.

It is a tau number, because it is divible by the number of its divisors (2240).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (638644124161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 223 ways as a sum of consecutive naturals, for example, 7694507479 + ... + 7694507561.

It is an arithmetic number, because the mean of its divisors is an integer number (1288096128).

Almost surely, 2^638644124160 is an apocalyptic number.

638644124160 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638644124160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1442667663360).

638644124160 is an abundant number, since it is smaller than the sum of its proper divisors (2246691202560).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

638644124160 is an equidigital number, since it uses as much as digits as its factorization.

638644124160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181 (or 150 counting only the distinct ones).

The product of its (nonzero) digits is 663552, while the sum is 45.

The spelling of 638644124160 in words is "six hundred thirty-eight billion, six hundred forty-four million, one hundred twenty-four thousand, one hundred sixty".