21195216 has 160 divisors (see below), whose sum is σ = 71582720. Its totient is φ = 5878656.

The previous prime is 21195199. The next prime is 21195221. The reversal of 21195216 is 61259112.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 21195216.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 129951 + ... + 130113.

It is an arithmetic number, because the mean of its divisors is an integer number (447392).

Almost surely, 2^21195216 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21195216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35791360).

21195216 is an abundant number, since it is smaller than the sum of its proper divisors (50387504).

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

21195216 is a wasteful number, since it uses less digits than its factorization.

21195216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230 (or 218 counting only the distinct ones).

The product of its digits is 1080, while the sum is 27.

The square root of 21195216 is about 4603.8262347747. The cubic root of 21195216 is about 276.7446808270.

The spelling of 21195216 in words is "twenty-one million, one hundred ninety-five thousand, two hundred sixteen".