21809632336128 has 1944 divisors, whose sum is σ = 88307168695200. Its totient is φ = 5127260995584.

The previous prime is 21809632336127. The next prime is 21809632336133. The reversal of 21809632336128 is 82163323690812.

21809632336128 is a `hidden beast` number, since 2 + 1 + 80 + 96 + 323 + 36 + 128 = 666.

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (21809632336127) by changing a digit.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 6162652183 + ... + 6162655721.

It is an arithmetic number, because the mean of its divisors is an integer number (45425498300).

Almost surely, 2^{21809632336128} is an apocalyptic number.

21809632336128 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 21809632336128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44153584347600).

21809632336128 is an abundant number, since it is smaller than the sum of its proper divisors (66497536359072).

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

21809632336128 is a wasteful number, since it uses less digits than its factorization.

21809632336128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3637 (or 3600 counting only the distinct ones).

The product of its (nonzero) digits is 4478976, while the sum is 54.

The spelling of 21809632336128 in words is "twenty-one trillion, eight hundred nine billion, six hundred thirty-two million, three hundred thirty-six thousand, one hundred twenty-eight".