21020241 has 24 divisors (see below), whose sum is σ = 31239040. Its totient is φ = 12561120.

The previous prime is 21020239. The next prime is 21020267. The reversal of 21020241 is 14202012.

It is not a de Polignac number, because 21020241 - 2¹ = 21020239 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 (21020231) 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 23 ways as a sum of consecutive naturals, for example, 28311 + ... + 29043.

Almost surely, 2^21020241 is an apocalyptic number.

It is an amenable number.

21020241 is a deficient number, since it is larger than the sum of its proper divisors (10218799).

21020241 is a wasteful number, since it uses less digits than its factorization.

21020241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 837 (or 826 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 21020241 is about 4584.7836372069. The cubic root of 21020241 is about 275.9810294670.

Adding to 21020241 its reverse (14202012), we get a palindrome (35222253).

The spelling of 21020241 in words is "twenty-one million, twenty thousand, two hundred forty-one".