638552801280 has 256 divisors, whose sum is σ = 2063339591040. Its totient is φ = 168614166528.

The previous prime is 638552801273. The next prime is 638552801281. The reversal of 638552801280 is 82108255836.

It is a tau number, because it is divible by the number of its divisors (256).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is not an unprimeable number, because it can be changed into a prime (638552801281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50620254 + ... + 50632866.

Almost surely, 2^638552801280 is an apocalyptic number.

638552801280 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 638552801280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1031669795520).

638552801280 is an abundant number, since it is smaller than the sum of its proper divisors (1424786789760).

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

638552801280 is a wasteful number, since it uses less digits than its factorization.

638552801280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12754 (or 12726 counting only the distinct ones).

The product of its (nonzero) digits is 921600, while the sum is 48.

The spelling of 638552801280 in words is "six hundred thirty-eight billion, five hundred fifty-two million, eight hundred one thousand, two hundred eighty".