21121100243 has 2 divisors, whose sum is σ = 21121100244. Its totient is φ = 21121100242.

The previous prime is 21121100227. The next prime is 21121100251. The reversal of 21121100243 is 34200112112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21121100243 - 2⁴ = 21121100227 is a prime.

It is a super-2 number, since 2×21121100243² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21121100443) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560550121 + 10560550122.

It is an arithmetic number, because the mean of its divisors is an integer number (10560550122).

Almost surely, 2^21121100243 is an apocalyptic number.

21121100243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121100243 is an equidigital number, since it uses as much as digits as its factorization.

21121100243 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 17.

Adding to 21121100243 its reverse (34200112112), we get a palindrome (55321212355).

The spelling of 21121100243 in words is "twenty-one billion, one hundred twenty-one million, one hundred thousand, two hundred forty-three".