21611143 has 2 divisors, whose sum is σ = 21611144. Its totient is φ = 21611142.

The previous prime is 21611087. The next prime is 21611159. The reversal of 21611143 is 34111612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21611143 - 2¹³ = 21602951 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21611143.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21611243) 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, 10805571 + 10805572.

It is an arithmetic number, because the mean of its divisors is an integer number (10805572).

Almost surely, 2^21611143 is an apocalyptic number.

21611143 is a deficient number, since it is larger than the sum of its proper divisors (1).

21611143 is an equidigital number, since it uses as much as digits as its factorization.

21611143 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 144, while the sum is 19.

The square root of 21611143 is about 4648.7786568087. The cubic root of 21611143 is about 278.5432118065.

Adding to 21611143 its reverse (34111612), we get a palindrome (55722755).

The spelling of 21611143 in words is "twenty-one million, six hundred eleven thousand, one hundred forty-three".