21578502368640 has 768 divisors, whose sum is σ = 84085163838720. Its totient is φ = 4687290187776.

The previous prime is 21578502368581. The next prime is 21578502368713. The reversal of 21578502368640 is 4686320587512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 149609199 + ... + 149753361.

It is an arithmetic number, because the mean of its divisors is an integer number (109485890415).

Almost surely, 2^{21578502368640} is an apocalyptic number.

21578502368640 is a gapful number since it is divisible by the number (20) 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 21578502368640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42042581919360).

21578502368640 is an abundant number, since it is smaller than the sum of its proper divisors (62506661470080).

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

21578502368640 is a wasteful number, since it uses less digits than its factorization.

21578502368640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144279 (or 144260 counting only the distinct ones).

The product of its (nonzero) digits is 19353600, while the sum is 57.

The spelling of 21578502368640 in words is "twenty-one trillion, five hundred seventy-eight billion, five hundred two million, three hundred sixty-eight thousand, six hundred forty".