20564189 has 2 divisors, whose sum is σ = 20564190. Its totient is φ = 20564188.

The previous prime is 20564177. The next prime is 20564207. The reversal of 20564189 is 98146502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18344089 + 2220100 = 4283^2 + 1490^2 .

It is a cyclic number.

It is not a de Polignac number, because 20564189 - 2¹² = 20560093 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20564389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10282094 + 10282095.

It is an arithmetic number, because the mean of its divisors is an integer number (10282095).

Almost surely, 2^20564189 is an apocalyptic number.

It is an amenable number.

20564189 is a deficient number, since it is larger than the sum of its proper divisors (1).

20564189 is an equidigital number, since it uses as much as digits as its factorization.

20564189 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 20564189 is about 4534.7755181486. The cubic root of 20564189 is about 273.9705377951.

The spelling of 20564189 in words is "twenty million, five hundred sixty-four thousand, one hundred eighty-nine".