20459209 has 2 divisors, whose sum is σ = 20459210. Its totient is φ = 20459208.

The previous prime is 20459203. The next prime is 20459227. The reversal of 20459209 is 90295402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20385225 + 73984 = 4515^2 + 272^2 .

It is a cyclic number.

It is not a de Polignac number, because 20459209 - 2¹¹ = 20457161 is a prime.

It is not a weakly prime, because it can be changed into another prime (20459203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10229604 + 10229605.

It is an arithmetic number, because the mean of its divisors is an integer number (10229605).

Almost surely, 2^20459209 is an apocalyptic number.

It is an amenable number.

20459209 is a deficient number, since it is larger than the sum of its proper divisors (1).

20459209 is an equidigital number, since it uses as much as digits as its factorization.

20459209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 20459209 is about 4523.1857136315. The cubic root of 20459209 is about 273.5035365012.

The spelling of 20459209 in words is "twenty million, four hundred fifty-nine thousand, two hundred nine".