21216856000 has 112 divisors (see below), whose sum is σ = 54828521280. Its totient is φ = 8117683200.

The previous prime is 21216855973. The next prime is 21216856021. The reversal of 21216856000 is 65861212.

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 126346 + ... + 241654.

Almost surely, 2^21216856000 is an apocalyptic number.

21216856000 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 21216856000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27414260640).

21216856000 is an abundant number, since it is smaller than the sum of its proper divisors (33611665280).

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

21216856000 is a wasteful number, since it uses less digits than its factorization.

21216856000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115359 (or 115339 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 31.

The spelling of 21216856000 in words is "twenty-one billion, two hundred sixteen million, eight hundred fifty-six thousand".