21300218726656 has 81 divisors (see below), whose sum is σ = 43258926851161. Its totient is φ = 10467457574912.

The previous prime is 21300218726569. The next prime is 21300218726669. The reversal of 21300218726656 is 65662781200312.

The square root of 21300218726656 is 4615216.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 14899723520256 + 6400495206400 = 3860016^2 + 2529920^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 4356761460 + ... + 4356766348.

Almost surely, 2^{21300218726656} is an apocalyptic number.

21300218726656 is the 4615216-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21300218726656

21300218726656 is an abundant number, since it is smaller than the sum of its proper divisors (21958708124505).

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

21300218726656 is an frugal number, since it uses more digits than its factorization.

21300218726656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9912 (or 4950 counting only the distinct ones).

The product of its (nonzero) digits is 1451520, while the sum is 49.

Adding to 21300218726656 its reverse (65662781200312), we get a palindrome (86962999926968).

The spelling of 21300218726656 in words is "twenty-one trillion, three hundred billion, two hundred eighteen million, seven hundred twenty-six thousand, six hundred fifty-six".