20310209 has 2 divisors, whose sum is σ = 20310210. Its totient is φ = 20310208.

The previous prime is 20310197. The next prime is 20310217. The reversal of 20310209 is 90201302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19891600 + 418609 = 4460^2 + 647^2 .

It is a cyclic number.

It is not a de Polignac number, because 20310209 - 2⁴ = 20310193 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20310709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10155104 + 10155105.

It is an arithmetic number, because the mean of its divisors is an integer number (10155105).

Almost surely, 2^20310209 is an apocalyptic number.

It is an amenable number.

20310209 is a deficient number, since it is larger than the sum of its proper divisors (1).

20310209 is an equidigital number, since it uses as much as digits as its factorization.

20310209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 20310209 is about 4506.6849235330. The cubic root of 20310209 is about 272.8379624059.

The spelling of 20310209 in words is "twenty million, three hundred ten thousand, two hundred nine".