20540243 has 2 divisors, whose sum is σ = 20540244. Its totient is φ = 20540242.

The previous prime is 20540239. The next prime is 20540249. The reversal of 20540243 is 34204502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20540243 - 2² = 20540239 is a prime.

It is equal to p_1302635 and since 20540243 and 1302635 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (20540249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10270121 + 10270122.

It is an arithmetic number, because the mean of its divisors is an integer number (10270122).

Almost surely, 2^20540243 is an apocalyptic number.

20540243 is a deficient number, since it is larger than the sum of its proper divisors (1).

20540243 is an equidigital number, since it uses as much as digits as its factorization.

20540243 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 960, while the sum is 20.

The square root of 20540243 is about 4532.1344860893. The cubic root of 20540243 is about 273.8641546937.

Adding to 20540243 its reverse (34204502), we get a palindrome (54744745).

It can be divided in two parts, 20540 and 243, that multiplied together give a triangular number (4991220 = T₃₁₅₉).

The spelling of 20540243 in words is "twenty million, five hundred forty thousand, two hundred forty-three".