21123365357664 has 1152 divisors, whose sum is σ = 69289758720000. Its totient is φ = 6064201728000.

The previous prime is 21123365357641. The next prime is 21123365357693. The reversal of 21123365357664 is 46675356332112.

21123365357664 is a `hidden beast` number, since 2 + 1 + 1 + 2 + 3 + 3 + 6 + 5 + 3 + 576 + 64 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 21123365357664.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 110593535809 + ... + 110593535999.

It is an arithmetic number, because the mean of its divisors is an integer number (60147360000).

Almost surely, 2^{21123365357664} is an apocalyptic number.

21123365357664 is a gapful number since it is divisible by the number (24) 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 21123365357664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34644879360000).

21123365357664 is an abundant number, since it is smaller than the sum of its proper divisors (48166393362336).

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

21123365357664 is a wasteful number, since it uses less digits than its factorization.

21123365357664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 572 (or 561 counting only the distinct ones).

The product of its digits is 16329600, while the sum is 54.

The spelling of 21123365357664 in words is "twenty-one trillion, one hundred twenty-three billion, three hundred sixty-five million, three hundred fifty-seven thousand, six hundred sixty-four".