20608409 has 2 divisors, whose sum is σ = 20608410. Its totient is φ = 20608408.

The previous prime is 20608387. The next prime is 20608439. The reversal of 20608409 is 90480602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20502784 + 105625 = 4528^2 + 325^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20608409 is a prime.

It is a super-2 number, since 2×20608409² = 849413043022562, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20608439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10304204 + 10304205.

It is an arithmetic number, because the mean of its divisors is an integer number (10304205).

Almost surely, 2^20608409 is an apocalyptic number.

It is an amenable number.

20608409 is a deficient number, since it is larger than the sum of its proper divisors (1).

20608409 is an equidigital number, since it uses as much as digits as its factorization.

20608409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 20608409 is about 4539.6485546791. The cubic root of 20608409 is about 274.1667738144.

The spelling of 20608409 in words is "twenty million, six hundred eight thousand, four hundred nine".