21103013 has 4 divisors (see below), whose sum is σ = 21113088. Its totient is φ = 21092940.

The previous prime is 21103003. The next prime is 21103021. The reversal of 21103013 is 31030112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21103013 - 2¹⁶ = 21037477 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21102985 and 21103003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21103003) 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, 581 + ... + 6522.

It is an arithmetic number, because the mean of its divisors is an integer number (5278272).

Almost surely, 2^21103013 is an apocalyptic number.

It is an amenable number.

21103013 is a deficient number, since it is larger than the sum of its proper divisors (10075).

21103013 is an equidigital number, since it uses as much as digits as its factorization.

21103013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10074.

The product of its (nonzero) digits is 18, while the sum is 11.

The square root of 21103013 is about 4593.8015847444. The cubic root of 21103013 is about 276.3428011415.

Adding to 21103013 its reverse (31030112), we get a palindrome (52133125).

The spelling of 21103013 in words is "twenty-one million, one hundred three thousand, thirteen".