21218041 has 8 divisors (see below), whose sum is σ = 24053120. Its totient is φ = 18554832.

The previous prime is 21218011. The next prime is 21218059. The reversal of 21218041 is 14081212.

It is a happy number.

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 21218041 - 2⁹ = 21217529 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is not an unprimeable number, because it can be changed into a prime (21218011) 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, 42705 + ... + 43198.

It is an arithmetic number, because the mean of its divisors is an integer number (3006640).

Almost surely, 2^21218041 is an apocalyptic number.

It is an amenable number.

21218041 is a deficient number, since it is larger than the sum of its proper divisors (2835079).

21218041 is a wasteful number, since it uses less digits than its factorization.

21218041 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85935.

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 21218041 is about 4606.3044840740. The cubic root of 21218041 is about 276.8439867462.

Adding to 21218041 its reverse (14081212), we get a palindrome (35299253).

The spelling of 21218041 in words is "twenty-one million, two hundred eighteen thousand, forty-one".