21627216 has 80 divisors (see below), whose sum is σ = 66870720. Its totient is φ = 6652800.

The previous prime is 21627197. The next prime is 21627223. The reversal of 21627216 is 61272612.

21627216 is a `hidden beast` number, since 21 + 627 + 2 + 16 = 666.

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 21627216.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3691 + ... + 7541.

It is an arithmetic number, because the mean of its divisors is an integer number (835884).

Almost surely, 2^21627216 is an apocalyptic number.

21627216 is a gapful number since it is divisible by the number (26) 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 21627216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33435360).

21627216 is an abundant number, since it is smaller than the sum of its proper divisors (45243504).

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

21627216 is a wasteful number, since it uses less digits than its factorization.

21627216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3881 (or 3869 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 21627216 is about 4650.5070691270. The cubic root of 21627216 is about 278.6122489632.

Adding to 21627216 its reverse (61272612), we get a palindrome (82899828).

The spelling of 21627216 in words is "twenty-one million, six hundred twenty-seven thousand, two hundred sixteen".