20508289 has 2 divisors, whose sum is σ = 20508290. Its totient is φ = 20508288.

The previous prime is 20508281. The next prime is 20508317. The reversal of 20508289 is 98280502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19492225 + 1016064 = 4415^2 + 1008^2 .

It is a cyclic number.

It is not a de Polignac number, because 20508289 - 2³ = 20508281 is a prime.

It is not a weakly prime, because it can be changed into another prime (20508281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10254144 + 10254145.

It is an arithmetic number, because the mean of its divisors is an integer number (10254145).

Almost surely, 2^20508289 is an apocalyptic number.

It is an amenable number.

20508289 is a deficient number, since it is larger than the sum of its proper divisors (1).

20508289 is an equidigital number, since it uses as much as digits as its factorization.

20508289 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11520, while the sum is 34.

The square root of 20508289 is about 4528.6078434768. The cubic root of 20508289 is about 273.7220661919.

The spelling of 20508289 in words is "twenty million, five hundred eight thousand, two hundred eighty-nine".