20022221 has 4 divisors (see below), whose sum is σ = 20296572. Its totient is φ = 19747872.

The previous prime is 20022203. The next prime is 20022229. The reversal of 20022221 is 12222002.

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 9066121 + 10956100 = 3011^2 + 3310^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20022221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20022229) 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, 137066 + ... + 137211.

It is an arithmetic number, because the mean of its divisors is an integer number (5074143).

Almost surely, 2^20022221 is an apocalyptic number.

It is an amenable number.

20022221 is a deficient number, since it is larger than the sum of its proper divisors (274351).

20022221 is an equidigital number, since it uses as much as digits as its factorization.

20022221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274350.

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

The square root of 20022221 is about 4474.6196486405. The cubic root of 20022221 is about 271.5422529082.

Adding to 20022221 its reverse (12222002), we get a palindrome (32244223).

The spelling of 20022221 in words is "twenty million, twenty-two thousand, two hundred twenty-one".