22021566 has 32 divisors (see below), whose sum is σ = 50979840. Its totient is φ = 6211296.

The previous prime is 22021561. The next prime is 22021567. The reversal of 22021566 is 66512022.

22021566 is a nontrivial binomial coefficient, being equal to C(6637, 2).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22021561) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 1 + ... + 6636.

It is an arithmetic number, because the mean of its divisors is an integer number (1593120).

Almost surely, 2^22021566 is an apocalyptic number.

22021566 is the 6636-th triangular number.

It is a practical number, because each smaller number is the sum of distinct divisors of 22021566, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25489920).

22021566 is an abundant number, since it is smaller than the sum of its proper divisors (28958274).

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

22021566 is a wasteful number, since it uses less digits than its factorization.

22021566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6728.

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 22021566 is about 4692.7141400260. The cubic root of 22021566 is about 280.2954619222.

Adding to 22021566 its reverse (66512022), we get a palindrome (88533588).

The spelling of 22021566 in words is "twenty-two million, twenty-one thousand, five hundred sixty-six".