20222561 has 2 divisors, whose sum is σ = 20222562. Its totient is φ = 20222560.

The previous prime is 20222557. The next prime is 20222569. The reversal of 20222561 is 16522202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17181025 + 3041536 = 4145^2 + 1744^2 .

It is a cyclic number.

It is not a de Polignac number, because 20222561 - 2² = 20222557 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (20222569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10111280 + 10111281.

It is an arithmetic number, because the mean of its divisors is an integer number (10111281).

Almost surely, 2^20222561 is an apocalyptic number.

It is an amenable number.

20222561 is a deficient number, since it is larger than the sum of its proper divisors (1).

20222561 is an equidigital number, since it uses as much as digits as its factorization.

20222561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 20222561 is about 4496.9501887390. The cubic root of 20222561 is about 272.4449222354. Note that the first 3 decimals are identical.

Adding to 20222561 its reverse (16522202), we get a palindrome (36744763).

The spelling of 20222561 in words is "twenty million, two hundred twenty-two thousand, five hundred sixty-one".