21622016 has 72 divisors (see below), whose sum is σ = 47645640. Its totient is φ = 9732096.

The previous prime is 21621997. The next prime is 21622033. The reversal of 21622016 is 61022612.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 92416 + 21529600 = 304^2 + 4640^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 242900 + ... + 242988.

It is an arithmetic number, because the mean of its divisors is an integer number (661745).

Almost surely, 2^21622016 is an apocalyptic number.

21622016 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 21622016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23822820).

21622016 is an abundant number, since it is smaller than the sum of its proper divisors (26023624).

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

21622016 is an equidigital number, since it uses as much as digits as its factorization.

21622016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191 (or 177 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 21622016 is about 4649.9479566980. The cubic root of 21622016 is about 278.5899175356.

Adding to 21622016 its reverse (61022612), we get a palindrome (82644628).

The spelling of 21622016 in words is "twenty-one million, six hundred twenty-two thousand, sixteen".