22021720 has 32 divisors (see below), whose sum is σ = 56628000. Its totient is φ = 7550208.

The previous prime is 22021711. The next prime is 22021721. The reversal of 22021720 is 2712022.

It is a junction number, because it is equal to n+sod(n) for n = 22021694 and 22021703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22021721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39045 + ... + 39604.

It is an arithmetic number, because the mean of its divisors is an integer number (1769625).

Almost surely, 2^22021720 is an apocalyptic number.

22021720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

22021720 is an abundant number, since it is smaller than the sum of its proper divisors (34606280).

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

22021720 is a wasteful number, since it uses less digits than its factorization.

22021720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78667 (or 78663 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 16.

The square root of 22021720 is about 4692.7305484121. The cubic root of 22021720 is about 280.2961153029.

Adding to 22021720 its reverse (2712022), we get a palindrome (24733742).

The spelling of 22021720 in words is "twenty-two million, twenty-one thousand, seven hundred twenty".