21042441 has 24 divisors (see below), whose sum is σ = 35091264. Its totient is φ = 11901600.

The previous prime is 21042419. The next prime is 21042449. The reversal of 21042441 is 14424012.

It is not a de Polignac number, because 21042441 - 2¹³ = 21034249 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21042449) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4710 + ... + 8016.

It is an arithmetic number, because the mean of its divisors is an integer number (1462136).

Almost surely, 2^21042441 is an apocalyptic number.

21042441 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21042441 is a deficient number, since it is larger than the sum of its proper divisors (14048823).

21042441 is a wasteful number, since it uses less digits than its factorization.

21042441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3421 (or 3418 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 21042441 is about 4587.2040503993. The cubic root of 21042441 is about 276.0781520965.

Adding to 21042441 its reverse (14424012), we get a palindrome (35466453).

The spelling of 21042441 in words is "twenty-one million, forty-two thousand, four hundred forty-one".