21868853 has 4 divisors (see below), whose sum is σ = 21878208. Its totient is φ = 21859500.

The previous prime is 21868849. The next prime is 21868909. The reversal of 21868853 is 35886812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21868853 - 2² = 21868849 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21868853.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21864853) 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 3 ways as a sum of consecutive naturals, for example, 2228 + ... + 6978.

It is an arithmetic number, because the mean of its divisors is an integer number (5469552).

Almost surely, 2^21868853 is an apocalyptic number.

It is an amenable number.

21868853 is a deficient number, since it is larger than the sum of its proper divisors (9355).

21868853 is an equidigital number, since it uses as much as digits as its factorization.

21868853 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9354.

The product of its digits is 92160, while the sum is 41.

The square root of 21868853 is about 4676.4145453542. The cubic root of 21868853 is about 279.6460365674.

The spelling of 21868853 in words is "twenty-one million, eight hundred sixty-eight thousand, eight hundred fifty-three".