21144173 has 2 divisors, whose sum is σ = 21144174. Its totient is φ = 21144172.

The previous prime is 21144121. The next prime is 21144181. The reversal of 21144173 is 37144112.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17156164 + 3988009 = 4142^2 + 1997^2 .

It is a cyclic number.

It is not a de Polignac number, because 21144173 - 2¹⁶ = 21078637 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21144373) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10572086 + 10572087.

It is an arithmetic number, because the mean of its divisors is an integer number (10572087).

Almost surely, 2^21144173 is an apocalyptic number.

It is an amenable number.

21144173 is a deficient number, since it is larger than the sum of its proper divisors (1).

21144173 is an equidigital number, since it uses as much as digits as its factorization.

21144173 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 672, while the sum is 23.

The square root of 21144173 is about 4598.2793521055. The cubic root of 21144173 is about 276.5223471110.

Adding to 21144173 its reverse (37144112), we get a palindrome (58288285).

The spelling of 21144173 in words is "twenty-one million, one hundred forty-four thousand, one hundred seventy-three".