20297209 has 2 divisors, whose sum is σ = 20297210. Its totient is φ = 20297208.

The previous prime is 20297191. The next prime is 20297213. The reversal of 20297209 is 90279202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14402025 + 5895184 = 3795^2 + 2428^2 .

It is a cyclic number.

It is not a de Polignac number, because 20297209 - 2⁵ = 20297177 is a prime.

It is not a weakly prime, because it can be changed into another prime (20297309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10148604 + 10148605.

It is an arithmetic number, because the mean of its divisors is an integer number (10148605).

Almost surely, 2^20297209 is an apocalyptic number.

It is an amenable number.

20297209 is a deficient number, since it is larger than the sum of its proper divisors (1).

20297209 is an equidigital number, since it uses as much as digits as its factorization.

20297209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4536, while the sum is 31.

The square root of 20297209 is about 4505.2423908154. The cubic root of 20297209 is about 272.7797379839.

The spelling of 20297209 in words is "twenty million, two hundred ninety-seven thousand, two hundred nine".