20506243 has 2 divisors, whose sum is σ = 20506244. Its totient is φ = 20506242.

The previous prime is 20506201. The next prime is 20506247. The reversal of 20506243 is 34260502.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20506243 is a prime.

It is not a weakly prime, because it can be changed into another prime (20506247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10253121 + 10253122.

It is an arithmetic number, because the mean of its divisors is an integer number (10253122).

Almost surely, 2^20506243 is an apocalyptic number.

20506243 is a deficient number, since it is larger than the sum of its proper divisors (1).

20506243 is an equidigital number, since it uses as much as digits as its factorization.

20506243 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1440, while the sum is 22.

The square root of 20506243 is about 4528.3819406053. The cubic root of 20506243 is about 273.7129633039.

Adding to 20506243 its reverse (34260502), we get a palindrome (54766745).

The spelling of 20506243 in words is "twenty million, five hundred six thousand, two hundred forty-three".