21043017 has 24 divisors (see below), whose sum is σ = 32252640. Its totient is φ = 13559400.

The previous prime is 21043007. The next prime is 21043019. The reversal of 21043017 is 71034012.

It is not a de Polignac number, because 21043017 - 2¹¹ = 21040969 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21043019) 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, 25542 + ... + 26352.

It is an arithmetic number, because the mean of its divisors is an integer number (1343860).

Almost surely, 2^21043017 is an apocalyptic number.

21043017 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21043017 is a deficient number, since it is larger than the sum of its proper divisors (11209623).

21043017 is an equidigital number, since it uses as much as digits as its factorization.

21043017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 882 (or 845 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 21043017 is about 4587.2668333115. The cubic root of 21043017 is about 276.0806711256.

Adding to 21043017 its reverse (71034012), we get a palindrome (92077029).

The spelling of 21043017 in words is "twenty-one million, forty-three thousand, seventeen".