21853673 has 4 divisors (see below), whose sum is σ = 22070148. Its totient is φ = 21637200.

The previous prime is 21853661. The next prime is 21853679. The reversal of 21853673 is 37635812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10778089 + 11075584 = 3283^2 + 3328^2 .

It is a cyclic number.

It is not a de Polignac number, because 21853673 - 2⁶ = 21853609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21853679) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 108086 + ... + 108287.

It is an arithmetic number, because the mean of its divisors is an integer number (5517537).

Almost surely, 2^21853673 is an apocalyptic number.

It is an amenable number.

21853673 is a deficient number, since it is larger than the sum of its proper divisors (216475).

21853673 is a wasteful number, since it uses less digits than its factorization.

21853673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216474.

The product of its digits is 30240, while the sum is 35.

The square root of 21853673 is about 4674.7912252848. The cubic root of 21853673 is about 279.5813172849.

The spelling of 21853673 in words is "twenty-one million, eight hundred fifty-three thousand, six hundred seventy-three".