21111241 has 2 divisors, whose sum is σ = 21111242. Its totient is φ = 21111240.

The previous prime is 21111239. The next prime is 21111247. The reversal of 21111241 is 14211112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11526025 + 9585216 = 3395^2 + 3096^2 .

It is a cyclic number.

It is not a de Polignac number, because 21111241 - 2¹ = 21111239 is a prime.

Together with 21111239, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21111247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555620 + 10555621.

It is an arithmetic number, because the mean of its divisors is an integer number (10555621).

Almost surely, 2^21111241 is an apocalyptic number.

It is an amenable number.

21111241 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111241 is an equidigital number, since it uses as much as digits as its factorization.

21111241 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16, while the sum is 13.

The square root of 21111241 is about 4594.6970520373. The cubic root of 21111241 is about 276.3787115448.

Adding to 21111241 its reverse (14211112), we get a palindrome (35322353).

The spelling of 21111241 in words is "twenty-one million, one hundred eleven thousand, two hundred forty-one".