21087103 has 4 divisors (see below), whose sum is σ = 21181888. Its totient is φ = 20992320.

The previous prime is 21087061. The next prime is 21087133. The reversal of 21087103 is 30178012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21087103 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 (21087133) 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, 47058 + ... + 47503.

It is an arithmetic number, because the mean of its divisors is an integer number (5295472).

Almost surely, 2^21087103 is an apocalyptic number.

21087103 is a deficient number, since it is larger than the sum of its proper divisors (94785).

21087103 is an equidigital number, since it uses as much as digits as its factorization.

21087103 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94784.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 21087103 is about 4592.0695769990. The cubic root of 21087103 is about 276.2733368217.

Subtracting 21087103 from its reverse (30178012), we obtain a palindrome (9090909).

The spelling of 21087103 in words is "twenty-one million, eighty-seven thousand, one hundred three".