22220021 has 4 divisors (see below), whose sum is σ = 22256652. Its totient is φ = 22183392.

The previous prime is 22219999. The next prime is 22220027. The reversal of 22220021 is 12002222.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4157521 + 18062500 = 2039^2 + 4250^2 .

It is a cyclic number.

It is not a de Polignac number, because 22220021 - 2¹⁰ = 22218997 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 22219984 and 22220011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22220027) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 17390 + ... + 18623.

It is an arithmetic number, because the mean of its divisors is an integer number (5564163).

Almost surely, 2^22220021 is an apocalyptic number.

It is an amenable number.

22220021 is a deficient number, since it is larger than the sum of its proper divisors (36631).

22220021 is an equidigital number, since it uses as much as digits as its factorization.

22220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36630.

The product of its (nonzero) digits is 32, while the sum is 11.

The square root of 22220021 is about 4713.8117272543. The cubic root of 22220021 is about 281.1349385471.

Adding to 22220021 its reverse (12002222), we get a palindrome (34222243).

The spelling of 22220021 in words is "twenty-two million, two hundred twenty thousand, twenty-one".