21001120243 has 2 divisors, whose sum is σ = 21001120244. Its totient is φ = 21001120242.

The previous prime is 21001120193. The next prime is 21001120247. The reversal of 21001120243 is 34202110012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21001120243 - 2⁹ = 21001119731 is a prime.

It is not a weakly prime, because it can be changed into another prime (21001120247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500560121 + 10500560122.

It is an arithmetic number, because the mean of its divisors is an integer number (10500560122).

Almost surely, 2^21001120243 is an apocalyptic number.

21001120243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001120243 is an equidigital number, since it uses as much as digits as its factorization.

21001120243 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21001120243 its reverse (34202110012), we get a palindrome (55203230255).

The spelling of 21001120243 in words is "twenty-one billion, one million, one hundred twenty thousand, two hundred forty-three".