21124349 has 2 divisors, whose sum is σ = 21124350. Its totient is φ = 21124348.

The previous prime is 21124343. The next prime is 21124351. The reversal of 21124349 is 94342112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14784025 + 6340324 = 3845^2 + 2518^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21124349 is a prime.

It is a Sophie Germain prime.

Together with 21124351, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21124343) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10562174 + 10562175.

It is an arithmetic number, because the mean of its divisors is an integer number (10562175).

Almost surely, 2^21124349 is an apocalyptic number.

It is an amenable number.

21124349 is a deficient number, since it is larger than the sum of its proper divisors (1).

21124349 is an equidigital number, since it uses as much as digits as its factorization.

21124349 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1728, while the sum is 26.

The square root of 21124349 is about 4596.1232577032. The cubic root of 21124349 is about 276.4359010237.

The spelling of 21124349 in words is "twenty-one million, one hundred twenty-four thousand, three hundred forty-nine".