168388638635520 has 2240 divisors, whose sum is σ = 637027940102400. Its totient is φ = 42631251886080.

The previous prime is 168388638635489. The next prime is 168388638635521. The reversal of 168388638635520 is 25536836883861.

It is a happy number.

168388638635520 is a `hidden beast` number, since 1 + 6 + 8 + 3 + 8 + 8 + 6 + 3 + 8 + 63 + 552 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (168388638635521) by changing a digit.

It is a polite number, since it can be written in 223 ways as a sum of consecutive naturals, for example, 537982870884 + ... + 537982871196.

It is an arithmetic number, because the mean of its divisors is an integer number (284387473260).

Almost surely, 2^{168388638635520} is an apocalyptic number.

168388638635520 is a gapful number since it is divisible by the number (10) 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 168388638635520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (318513970051200).

168388638635520 is an abundant number, since it is smaller than the sum of its proper divisors (468639301466880).

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

168388638635520 is an frugal number, since it uses more digits than its factorization.

168388638635520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 563 (or 532 counting only the distinct ones).

The product of its (nonzero) digits is 1194393600, while the sum is 72.

The spelling of 168388638635520 in words is "one hundred sixty-eight trillion, three hundred eighty-eight billion, six hundred thirty-eight million, six hundred thirty-five thousand, five hundred twenty".