21042143 has 8 divisors (see below), whose sum is σ = 21636720. Its totient is φ = 20451520.

The previous prime is 21042127. The next prime is 21042157. The reversal of 21042143 is 34124012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21042143 - 2⁴ = 21042127 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21042103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12188 + ... + 13806.

It is an arithmetic number, because the mean of its divisors is an integer number (2704590).

Almost surely, 2^21042143 is an apocalyptic number.

21042143 is a deficient number, since it is larger than the sum of its proper divisors (594577).

21042143 is a wasteful number, since it uses less digits than its factorization.

21042143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1977.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 21042143 is about 4587.1715686248. The cubic root of 21042143 is about 276.0768488307.

Adding to 21042143 its reverse (34124012), we get a palindrome (55166155).

The spelling of 21042143 in words is "twenty-one million, forty-two thousand, one hundred forty-three".