21111143 has 2 divisors, whose sum is σ = 21111144. Its totient is φ = 21111142.

The previous prime is 21111113. The next prime is 21111149. The reversal of 21111143 is 34111112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21111143 - 2²² = 16916839 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 (21111149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555571 + 10555572.

It is an arithmetic number, because the mean of its divisors is an integer number (10555572).

Almost surely, 2^21111143 is an apocalyptic number.

21111143 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111143 is an equidigital number, since it uses as much as digits as its factorization.

21111143 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24, while the sum is 14.

The square root of 21111143 is about 4594.6863875568. The cubic root of 21111143 is about 276.3782838871.

Adding to 21111143 its reverse (34111112), we get a palindrome (55222255).

The spelling of 21111143 in words is "twenty-one million, one hundred eleven thousand, one hundred forty-three".