21124853 has 2 divisors, whose sum is σ = 21124854. Its totient is φ = 21124852.

The previous prime is 21124841. The next prime is 21124867. The reversal of 21124853 is 35842112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11992369 + 9132484 = 3463^2 + 3022^2 .

It is a cyclic number.

It is not a de Polignac number, because 21124853 - 2²² = 16930549 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is equal to p_1337372 and since 21124853 and 1337372 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21124823) 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, 10562426 + 10562427.

It is an arithmetic number, because the mean of its divisors is an integer number (10562427).

Almost surely, 2^21124853 is an apocalyptic number.

It is an amenable number.

21124853 is a deficient number, since it is larger than the sum of its proper divisors (1).

21124853 is an equidigital number, since it uses as much as digits as its factorization.

21124853 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1920, while the sum is 26.

The square root of 21124853 is about 4596.1780861929. The cubic root of 21124853 is about 276.4380994754.

Adding to 21124853 its reverse (35842112), we get a palindrome (56966965).

The spelling of 21124853 in words is "twenty-one million, one hundred twenty-four thousand, eight hundred fifty-three".