21033013 has 4 divisors (see below), whose sum is σ = 21044908. Its totient is φ = 21021120.

The previous prime is 21033011. The next prime is 21033053. The reversal of 21033013 is 31033012.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 15984004 + 5049009 = 3998^2 + 2247^2 .

It is a cyclic number.

It is not a de Polignac number, because 21033013 - 2¹ = 21033011 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21032984 and 21033002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21033011) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2706 + ... + 7027.

It is an arithmetic number, because the mean of its divisors is an integer number (5261227).

Almost surely, 2^21033013 is an apocalyptic number.

It is an amenable number.

21033013 is a deficient number, since it is larger than the sum of its proper divisors (11895).

21033013 is an equidigital number, since it uses as much as digits as its factorization.

21033013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11894.

The product of its (nonzero) digits is 54, while the sum is 13.

The square root of 21033013 is about 4586.1762940384. The cubic root of 21033013 is about 276.0369139523.

Adding to 21033013 its reverse (31033012), we get a palindrome (52066025).

Subtracting 21033013 from its reverse (31033012), we obtain a palindrome (9999999).

The spelling of 21033013 in words is "twenty-one million, thirty-three thousand, thirteen".