21104173 has 4 divisors (see below), whose sum is σ = 21142620. Its totient is φ = 21065728.

The previous prime is 21104143. The next prime is 21104203. The reversal of 21104173 is 37140112.

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

It is an interprime number because it is at equal distance from previous prime (21104143) and next prime (21104203).

It can be written as a sum of positive squares in 2 ways, for example, as 3143529 + 17960644 = 1773^2 + 4238^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21104173 is a prime.

It is a super-2 number, since 2×21104173² = 890772236027858, which contains 22 as substring.

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 21104173.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21104143) 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, 18388 + ... + 19501.

It is an arithmetic number, because the mean of its divisors is an integer number (5285655).

Almost surely, 2^21104173 is an apocalyptic number.

It is an amenable number.

21104173 is a deficient number, since it is larger than the sum of its proper divisors (38447).

21104173 is an equidigital number, since it uses as much as digits as its factorization.

21104173 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38446.

The product of its (nonzero) digits is 168, while the sum is 19.

The square root of 21104173 is about 4593.9278400950. The cubic root of 21104173 is about 276.3478644276.

Adding to 21104173 its reverse (37140112), we get a palindrome (58244285).

The spelling of 21104173 in words is "twenty-one million, one hundred four thousand, one hundred seventy-three".