20225561 has 2 divisors, whose sum is σ = 20225562. Its totient is φ = 20225560.

The previous prime is 20225539. The next prime is 20225573. The reversal of 20225561 is 16552202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18318400 + 1907161 = 4280^2 + 1381^2 .

It is a cyclic number.

It is not a de Polignac number, because 20225561 - 2¹⁰ = 20224537 is a prime.

It is not a weakly prime, because it can be changed into another prime (20225521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10112780 + 10112781.

It is an arithmetic number, because the mean of its divisors is an integer number (10112781).

Almost surely, 2^20225561 is an apocalyptic number.

It is an amenable number.

20225561 is a deficient number, since it is larger than the sum of its proper divisors (1).

20225561 is an equidigital number, since it uses as much as digits as its factorization.

20225561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 20225561 is about 4497.2837357676. The cubic root of 20225561 is about 272.4583938947.

Adding to 20225561 its reverse (16552202), we get a palindrome (36777763).

The spelling of 20225561 in words is "twenty million, two hundred twenty-five thousand, five hundred sixty-one".