21215670336 has 525 divisors, whose sum is σ = 77729927979. Its totient is φ = 5705054208.

The previous prime is 21215670317. The next prime is 21215670337. The reversal of 21215670336 is 63307651212.

The square root of 21215670336 is 145656.

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

It can be written as a sum of positive squares in 2 ways, for example, as 6584348736 + 14631321600 = 81144^2 + 120960^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21215670336.

It is not an unprimeable number, because it can be changed into a prime (21215670337) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 74 ways as a sum of consecutive naturals, for example, 1247980600 + ... + 1247980616.

Almost surely, 2^21215670336 is an apocalyptic number.

21215670336 is the 145656-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21215670336

21215670336 is an abundant number, since it is smaller than the sum of its proper divisors (56514257643).

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

21215670336 is an frugal number, since it uses more digits than its factorization.

21215670336 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106 (or 29 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 36.

Multiplying 21215670336 by its sum of digits (36), we get a square (763764132096 = 873936²).

21215670336 divided by its sum of digits (36) gives a square (589324176 = 24276²).

The spelling of 21215670336 in words is "twenty-one billion, two hundred fifteen million, six hundred seventy thousand, three hundred thirty-six".