20010209 has 2 divisors, whose sum is σ = 20010210. Its totient is φ = 20010208.

The previous prime is 20010197. The next prime is 20010217. The reversal of 20010209 is 90201002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19936225 + 73984 = 4465^2 + 272^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20010209 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20010193 and 20010202.

It is not a weakly prime, because it can be changed into another prime (20010239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10005104 + 10005105.

It is an arithmetic number, because the mean of its divisors is an integer number (10005105).

Almost surely, 2^20010209 is an apocalyptic number.

It is an amenable number.

20010209 is a deficient number, since it is larger than the sum of its proper divisors (1).

20010209 is an equidigital number, since it uses as much as digits as its factorization.

20010209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36, while the sum is 14.

The square root of 20010209 is about 4473.2772102788. The cubic root of 20010209 is about 271.4879396189.

The spelling of 20010209 in words is "twenty million, ten thousand, two hundred nine".