21216835600 has 45 divisors (see below), whose sum is σ = 50980447453. Its totient is φ = 8485568960.

The previous prime is 21216835589. The next prime is 21216835613. The reversal of 21216835600 is 653861212.

The square root of 21216835600 is 145660.

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., 7638060816 + 13578774784 = 87396^2 + 116528^2 .

It is a super-2 number, since 2×21216835600² (a number of 21 digits) contains 22 as substring.

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, 2909559 + ... + 2916841.

Almost surely, 2^21216835600 is an apocalyptic number.

21216835600 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

21216835600 is the 145660-th square number.

It is an amenable number.

21216835600 is an abundant number, since it is smaller than the sum of its proper divisors (29763611853).

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

21216835600 is an frugal number, since it uses more digits than its factorization.

21216835600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14584 (or 7290 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 34.

The spelling of 21216835600 in words is "twenty-one billion, two hundred sixteen million, eight hundred thirty-five thousand, six hundred".