21616853 has 2 divisors, whose sum is σ = 21616854. Its totient is φ = 21616852.

The previous prime is 21616841. The next prime is 21616883. The reversal of 21616853 is 35861612.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17783089 + 3833764 = 4217^2 + 1958^2 .

It is a cyclic number.

It is not a de Polignac number, because 21616853 - 2⁶ = 21616789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21616823) 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, 10808426 + 10808427.

It is an arithmetic number, because the mean of its divisors is an integer number (10808427).

Almost surely, 2^21616853 is an apocalyptic number.

It is an amenable number.

21616853 is a deficient number, since it is larger than the sum of its proper divisors (1).

21616853 is an equidigital number, since it uses as much as digits as its factorization.

21616853 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8640, while the sum is 32.

The square root of 21616853 is about 4649.3927560489. The cubic root of 21616853 is about 278.5677414621.

The spelling of 21616853 in words is "twenty-one million, six hundred sixteen thousand, eight hundred fifty-three".