21120103 has 4 divisors (see below), whose sum is σ = 22362480. Its totient is φ = 19877728.

The previous prime is 21120089. The next prime is 21120109. The reversal of 21120103 is 30102112.

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

It is a cyclic number.

It is not a de Polignac number, because 21120103 - 2²¹ = 19022951 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21120103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120109) 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, 621163 + ... + 621196.

It is an arithmetic number, because the mean of its divisors is an integer number (5590620).

Almost surely, 2^21120103 is an apocalyptic number.

21120103 is a deficient number, since it is larger than the sum of its proper divisors (1242377).

21120103 is a wasteful number, since it uses less digits than its factorization.

21120103 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1242376.

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 21120103 is about 4595.6613234659. The cubic root of 21120103 is about 276.4173785517.

Adding to 21120103 its reverse (30102112), we get a palindrome (51222215).

Subtracting 21120103 from its reverse (30102112), we obtain a square (8982009 = 2997²).

The spelling of 21120103 in words is "twenty-one million, one hundred twenty thousand, one hundred three".