21216600363520 has 80 divisors (see below), whose sum is σ = 50893755236280. Its totient is φ = 8482696167424.

The previous prime is 21216600363443. The next prime is 21216600363601. The reversal of 21216600363520 is 2536300661212.

It can be written as a sum of positive squares in 4 ways, for example, as 18152644190464 + 3063956173056 = 4260592^2 + 1750416^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×21216600363520² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21216600363520.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 3586986 + ... + 7436374.

Almost surely, 2^{21216600363520} is an apocalyptic number.

21216600363520 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 21216600363520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25446877618140).

21216600363520 is an abundant number, since it is smaller than the sum of its proper divisors (29677154872760).

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

21216600363520 is an equidigital number, since it uses as much as digits as its factorization.

21216600363520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3851565 (or 3851549 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 37.

The spelling of 21216600363520 in words is "twenty-one trillion, two hundred sixteen billion, six hundred million, three hundred sixty-three thousand, five hundred twenty".