21617143 has 2 divisors, whose sum is σ = 21617144. Its totient is φ = 21617142.

The previous prime is 21617111. The next prime is 21617191. The reversal of 21617143 is 34171612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21617143 - 2⁵ = 21617111 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21617243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10808571 + 10808572.

It is an arithmetic number, because the mean of its divisors is an integer number (10808572).

Almost surely, 2^21617143 is an apocalyptic number.

21617143 is a deficient number, since it is larger than the sum of its proper divisors (1).

21617143 is an equidigital number, since it uses as much as digits as its factorization.

21617143 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1008, while the sum is 25.

The square root of 21617143 is about 4649.4239428127. The cubic root of 21617143 is about 278.5689871612.

Adding to 21617143 its reverse (34171612), we get a palindrome (55788755).

The spelling of 21617143 in words is "twenty-one million, six hundred seventeen thousand, one hundred forty-three".