21042041 has 4 divisors (see below), whose sum is σ = 21489792. Its totient is φ = 20594292.

The previous prime is 21042017. The next prime is 21042053. The reversal of 21042041 is 14024012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21042041 - 2¹⁸ = 20779897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21042841) 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 in 3 ways as a sum of consecutive naturals, for example, 223805 + ... + 223898.

It is an arithmetic number, because the mean of its divisors is an integer number (5372448).

Almost surely, 2^21042041 is an apocalyptic number.

It is an amenable number.

21042041 is a deficient number, since it is larger than the sum of its proper divisors (447751).

21042041 is an equidigital number, since it uses as much as digits as its factorization.

21042041 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 447750.

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 21042041 is about 4587.1604506492. The cubic root of 21042041 is about 276.0764027437.

Adding to 21042041 its reverse (14024012), we get a palindrome (35066053).

The spelling of 21042041 in words is "twenty-one million, forty-two thousand, forty-one".