21020041 has 16 divisors (see below), whose sum is σ = 26317440.
Its totient is φ = 16369920.
The previous prime is 21020039. The next prime is 21020053. The reversal of 21020041 is 14002012.
Adding to 21020041 its reverse (14002012), we get a palindrome (35022053).
It is not a de Polignac number, because 21020041 - 21 = 21020039 is a prime.
It is a Duffinian number.
It is not an unprimeable number, because it can be changed into a prime (21020011) 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 15 ways as a sum of consecutive naturals, for example, 406 + ... + 6496.
It is an arithmetic number, because the mean of its divisors is an integer number (1644840).
Almost surely, 221020041 is an apocalyptic number.
It is an amenable number.
21020041 is a deficient number, since it is larger than the sum of its proper divisors (5297399).
21020041 is a wasteful number, since it uses less digits than its factorization.
21020041 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 6144.
The product of its (nonzero) digits is 16, while the sum is 10.
The square root of 21020041 is about 4584.7618258749.
The cubic root of 21020041 is about 275.9801541776.
The spelling of 21020041 in words is "twenty-one million, twenty thousand, forty-one".