21202420243 has 2 divisors, whose sum is σ = 21202420244. Its totient is φ = 21202420242.

The previous prime is 21202420157. The next prime is 21202420259. The reversal of 21202420243 is 34202420212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21202420243 is a prime.

It is not a weakly prime, because it can be changed into another prime (21202420543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601210121 + 10601210122.

It is an arithmetic number, because the mean of its divisors is an integer number (10601210122).

Almost surely, 2^21202420243 is an apocalyptic number.

21202420243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21202420243 is an equidigital number, since it uses as much as digits as its factorization.

21202420243 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1536, while the sum is 22.

Adding to 21202420243 its reverse (34202420212), we get a palindrome (55404840455).

The spelling of 21202420243 in words is "twenty-one billion, two hundred two million, four hundred twenty thousand, two hundred forty-three".