20309243 has 2 divisors, whose sum is σ = 20309244. Its totient is φ = 20309242.

The previous prime is 20309213. The next prime is 20309269. The reversal of 20309243 is 34290302.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20309243 - 2¹⁰ = 20308219 is a prime.

It is not a weakly prime, because it can be changed into another prime (20309213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10154621 + 10154622.

It is an arithmetic number, because the mean of its divisors is an integer number (10154622).

Almost surely, 2^20309243 is an apocalyptic number.

20309243 is a deficient number, since it is larger than the sum of its proper divisors (1).

20309243 is an equidigital number, since it uses as much as digits as its factorization.

20309243 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1296, while the sum is 23.

The square root of 20309243 is about 4506.5777481366. The cubic root of 20309243 is about 272.8336367381.

Adding to 20309243 its reverse (34290302), we get a palindrome (54599545).

The spelling of 20309243 in words is "twenty million, three hundred nine thousand, two hundred forty-three".