21742135 has 8 divisors (see below), whose sum is σ = 26117856. Its totient is φ = 17375520.

The previous prime is 21742111. The next prime is 21742139. The reversal of 21742135 is 53124712.

It is a happy number.

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

It is not a de Polignac number, because 21742135 - 2²¹ = 19644983 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 (21742139) 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, 5245 + ... + 8425.

It is an arithmetic number, because the mean of its divisors is an integer number (3264732).

Almost surely, 2^21742135 is an apocalyptic number.

21742135 is a deficient number, since it is larger than the sum of its proper divisors (4375721).

21742135 is a wasteful number, since it uses less digits than its factorization.

21742135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4553.

The product of its digits is 1680, while the sum is 25.

The square root of 21742135 is about 4662.8462337933. The cubic root of 21742135 is about 279.1048581760.

Adding to 21742135 its reverse (53124712), we get a palindrome (74866847).

The spelling of 21742135 in words is "twenty-one million, seven hundred forty-two thousand, one hundred thirty-five".