21215068821504 has 144 divisors (see below), whose sum is σ = 61405951566960. Its totient is φ = 7056346890240.

The previous prime is 21215068821491. The next prime is 21215068821523. The reversal of 21215068821504 is 40512886051212.

21215068821504 is a `hidden beast` number, since 2 + 1 + 2 + 1 + 5 + 0 + 68 + 82 + 1 + 504 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-3 number, since 3×21215068821504³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 21215068821504.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7248789 + ... + 9745515.

It is an arithmetic number, because the mean of its divisors is an integer number (426430219215).

Almost surely, 2^{21215068821504} is an apocalyptic number.

21215068821504 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 21215068821504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30702975783480).

21215068821504 is an abundant number, since it is smaller than the sum of its proper divisors (40190882745456).

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

21215068821504 is a wasteful number, since it uses less digits than its factorization.

21215068821504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2497216 (or 2497193 counting only the distinct ones).

The product of its (nonzero) digits is 307200, while the sum is 45.

The spelling of 21215068821504 in words is "twenty-one trillion, two hundred fifteen billion, sixty-eight million, eight hundred twenty-one thousand, five hundred four".