21513103 has 4 divisors (see below), whose sum is σ = 21523048. Its totient is φ = 21503160.

The previous prime is 21513091. The next prime is 21513113. The reversal of 21513103 is 30131512.

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 is a cyclic number.

It is not a de Polignac number, because 21513103 - 2⁹ = 21512591 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 (21513113) 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 3 ways as a sum of consecutive naturals, for example, 201 + ... + 6562.

It is an arithmetic number, because the mean of its divisors is an integer number (5380762).

Almost surely, 2^21513103 is an apocalyptic number.

21513103 is a deficient number, since it is larger than the sum of its proper divisors (9945).

21513103 is an equidigital number, since it uses as much as digits as its factorization.

21513103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9944.

The product of its (nonzero) digits is 90, while the sum is 16.

The square root of 21513103 is about 4638.2219653656. The cubic root of 21513103 is about 278.1213649822.

Adding to 21513103 its reverse (30131512), we get a palindrome (51644615).

The spelling of 21513103 in words is "twenty-one million, five hundred thirteen thousand, one hundred three".