22018221 has 18 divisors (see below), whose sum is σ = 32949930. Its totient is φ = 14167776.

The previous prime is 22018211. The next prime is 22018223. The reversal of 22018221 is 12281022.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 7502121 + 14516100 = 2739^2 + 3810^2 .

It is not a de Polignac number, because 22018221 - 2¹⁷ = 21887149 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 22018194 and 22018203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22018223) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 6115 + ... + 9023.

Almost surely, 2^22018221 is an apocalyptic number.

It is an amenable number.

22018221 is a deficient number, since it is larger than the sum of its proper divisors (10931709).

22018221 is a wasteful number, since it uses less digits than its factorization.

22018221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2973 (or 2941 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 22018221 is about 4692.3577229363. The cubic root of 22018221 is about 280.2812692319.

Adding to 22018221 its reverse (12281022), we get a palindrome (34299243).

The spelling of 22018221 in words is "twenty-two million, eighteen thousand, two hundred twenty-one".