21726143 has 2 divisors, whose sum is σ = 21726144. Its totient is φ = 21726142.

The previous prime is 21726121. The next prime is 21726151. The reversal of 21726143 is 34162712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21726143 - 2¹² = 21722047 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21726113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10863071 + 10863072.

It is an arithmetic number, because the mean of its divisors is an integer number (10863072).

Almost surely, 2^21726143 is an apocalyptic number.

21726143 is a deficient number, since it is larger than the sum of its proper divisors (1).

21726143 is an equidigital number, since it uses as much as digits as its factorization.

21726143 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2016, while the sum is 26.

The square root of 21726143 is about 4661.1310859061. The cubic root of 21726143 is about 279.0364113611.

Adding to 21726143 its reverse (34162712), we get a palindrome (55888855).

It can be divided in two parts, 21 and 726143, that multiplied together give a triangular number (15249003 = T₅₅₂₂).

The spelling of 21726143 in words is "twenty-one million, seven hundred twenty-six thousand, one hundred forty-three".