21435853 has 2 divisors, whose sum is σ = 21435854. Its totient is φ = 21435852.

The previous prime is 21435833. The next prime is 21435859. The reversal of 21435853 is 35853412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11682724 + 9753129 = 3418^2 + 3123^2 .

It is a cyclic number.

It is not a de Polignac number, because 21435853 - 2⁹ = 21435341 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21435859) 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, 10717926 + 10717927.

It is an arithmetic number, because the mean of its divisors is an integer number (10717927).

Almost surely, 2^21435853 is an apocalyptic number.

It is an amenable number.

21435853 is a deficient number, since it is larger than the sum of its proper divisors (1).

21435853 is an equidigital number, since it uses as much as digits as its factorization.

21435853 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14400, while the sum is 31.

The square root of 21435853 is about 4629.8869316647. The cubic root of 21435853 is about 277.7880697639.

The spelling of 21435853 in words is "twenty-one million, four hundred thirty-five thousand, eight hundred fifty-three".