21012301243 has 2 divisors, whose sum is σ = 21012301244. Its totient is φ = 21012301242.

The previous prime is 21012301231. The next prime is 21012301249. The reversal of 21012301243 is 34210321012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21012301243 - 2⁹ = 21012300731 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21012301243.

It is not a weakly prime, because it can be changed into another prime (21012301249) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506150621 + 10506150622.

It is an arithmetic number, because the mean of its divisors is an integer number (10506150622).

Almost surely, 2^21012301243 is an apocalyptic number.

21012301243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012301243 is an equidigital number, since it uses as much as digits as its factorization.

21012301243 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 21012301243 its reverse (34210321012), we get a palindrome (55222622255).

The spelling of 21012301243 in words is "twenty-one billion, twelve million, three hundred one thousand, two hundred forty-three".