21207853 has 2 divisors, whose sum is σ = 21207854. Its totient is φ = 21207852.

The previous prime is 21207847. The next prime is 21207869. The reversal of 21207853 is 35870212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20820969 + 386884 = 4563^2 + 622^2 .

It is a cyclic number.

It is not a de Polignac number, because 21207853 - 2⁹ = 21207341 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21205853) 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, 10603926 + 10603927.

It is an arithmetic number, because the mean of its divisors is an integer number (10603927).

Almost surely, 2^21207853 is an apocalyptic number.

It is an amenable number.

21207853 is a deficient number, since it is larger than the sum of its proper divisors (1).

21207853 is an equidigital number, since it uses as much as digits as its factorization.

21207853 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 21207853 is about 4605.1984756360. The cubic root of 21207853 is about 276.7996700869.

The spelling of 21207853 in words is "twenty-one million, two hundred seven thousand, eight hundred fifty-three".