22216021 has 4 divisors (see below), whose sum is σ = 22816492. Its totient is φ = 21615552.

The previous prime is 22216009. The next prime is 22216031. The reversal of 22216021 is 12061222.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12061222 = 2 ⋅6030611.

It can be written as a sum of positive squares in 2 ways, for example, as 20295025 + 1920996 = 4505^2 + 1386^2 .

It is a cyclic number.

It is not a de Polignac number, because 22216021 - 2⁵ = 22215989 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 22215986 and 22216004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22216031) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 300180 + ... + 300253.

It is an arithmetic number, because the mean of its divisors is an integer number (5704123).

Almost surely, 2^22216021 is an apocalyptic number.

It is an amenable number.

22216021 is a deficient number, since it is larger than the sum of its proper divisors (600471).

22216021 is an equidigital number, since it uses as much as digits as its factorization.

22216021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 600470.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 22216021 is about 4713.3874230748. The cubic root of 22216021 is about 281.1180677674.

Adding to 22216021 its reverse (12061222), we get a palindrome (34277243).

The spelling of 22216021 in words is "twenty-two million, two hundred sixteen thousand, twenty-one".