20611609 has 2 divisors, whose sum is σ = 20611610. Its totient is φ = 20611608.

The previous prime is 20611601. The next prime is 20611649. The reversal of 20611609 is 90611602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20611600 + 9 = 4540^2 + 3^2 .

It is a cyclic number.

It is not a de Polignac number, because 20611609 - 2³ = 20611601 is a prime.

It is not a weakly prime, because it can be changed into another prime (20611601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10305804 + 10305805.

It is an arithmetic number, because the mean of its divisors is an integer number (10305805).

Almost surely, 2^20611609 is an apocalyptic number.

It is an amenable number.

20611609 is a deficient number, since it is larger than the sum of its proper divisors (1).

20611609 is an equidigital number, since it uses as much as digits as its factorization.

20611609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 20611609 is about 4540.0009911893. Note that the first 3 decimals coincide. The cubic root of 20611609 is about 274.1809636251.

The spelling of 20611609 in words is "twenty million, six hundred eleven thousand, six hundred nine".