21853385 has 12 divisors (see below), whose sum is σ = 27164748. Its totient is φ = 16876608.

The previous prime is 21853379. The next prime is 21853387. The reversal of 21853385 is 58335812.

It can be written as a sum of positive squares in 6 ways, for example, as 100489 + 21752896 = 317^2 + 4664^2 .

It is not a de Polignac number, because 21853385 - 2⁸ = 21853129 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21853387) 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 in 11 ways as a sum of consecutive naturals, for example, 1607 + ... + 6803.

It is an arithmetic number, because the mean of its divisors is an integer number (2263729).

Almost surely, 2^21853385 is an apocalyptic number.

It is an amenable number.

21853385 is a deficient number, since it is larger than the sum of its proper divisors (5311363).

21853385 is an equidigital number, since it uses as much as digits as its factorization.

21853385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5260 (or 5231 counting only the distinct ones).

The product of its digits is 28800, while the sum is 35.

The square root of 21853385 is about 4674.7604216687. The cubic root of 21853385 is about 279.5800891195.

The spelling of 21853385 in words is "twenty-one million, eight hundred fifty-three thousand, three hundred eighty-five".