21838757728788 has 960 divisors, whose sum is σ = 78914146848768. Its totient is φ = 5083130142720.

The previous prime is 21838757728787. The next prime is 21838757728817. The reversal of 21838757728788 is 88782775783812.

21838757728788 is a `hidden beast` number, since 2 + 1 + 8 + 38 + 7 + 577 + 2 + 8 + 7 + 8 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21838757728783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 319 ways as a sum of consecutive naturals, for example, 2328965956 + ... + 2328975332.

Almost surely, 2^{21838757728788} is an apocalyptic number.

21838757728788 is a gapful number since it is divisible by the number (28) 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 21838757728788, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39457073424384).

21838757728788 is an abundant number, since it is smaller than the sum of its proper divisors (57075389119980).

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

21838757728788 is a wasteful number, since it uses less digits than its factorization.

21838757728788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9634 (or 9623 counting only the distinct ones).

The product of its digits is 4720558080, while the sum is 81.

The spelling of 21838757728788 in words is "twenty-one trillion, eight hundred thirty-eight billion, seven hundred fifty-seven million, seven hundred twenty-eight thousand, seven hundred eighty-eight".