638623905360 has 640 divisors, whose sum is σ = 2461306466304. Its totient is φ = 133670338560.

The previous prime is 638623905323. The next prime is 638623905379. The reversal of 638623905360 is 63509326836.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is an unprimeable number.

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 in 127 ways as a sum of consecutive naturals, for example, 158820150 + ... + 158824170.

Almost surely, 2^638623905360 is an apocalyptic number.

638623905360 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 638623905360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1230653233152).

638623905360 is an abundant number, since it is smaller than the sum of its proper divisors (1822682560944).

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

638623905360 is a wasteful number, since it uses less digits than its factorization.

638623905360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4211 (or 4205 counting only the distinct ones).

The product of its (nonzero) digits is 4199040, while the sum is 51.

The spelling of 638623905360 in words is "six hundred thirty-eight billion, six hundred twenty-three million, nine hundred five thousand, three hundred sixty".