20221684 has 48 divisors (see below), whose sum is σ = 42134400. Its totient is φ = 8311680.

The previous prime is 20221679. The next prime is 20221693. The reversal of 20221684 is 48612202.

20221684 = T₄₄₇ + T₄₄₈ + ... + T₅₉₄.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 135642 + ... + 135790.

It is an arithmetic number, because the mean of its divisors is an integer number (877800).

Almost surely, 2^20221684 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 20221684, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21067200).

20221684 is an abundant number, since it is smaller than the sum of its proper divisors (21912716).

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

20221684 is a wasteful number, since it uses less digits than its factorization.

20221684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328 (or 326 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 25.

The square root of 20221684 is about 4496.8526771510. The cubic root of 20221684 is about 272.4409837687.

Adding to 20221684 its reverse (48612202), we get a palindrome (68833886).

The spelling of 20221684 in words is "twenty million, two hundred twenty-one thousand, six hundred eighty-four".