21021103 has 8 divisors (see below), whose sum is σ = 21982176. Its totient is φ = 20064000.

The previous prime is 21021101. The next prime is 21021107. The reversal of 21021103 is 30112012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21021103 - 2¹ = 21021101 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21021103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021101) 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 7 ways as a sum of consecutive naturals, for example, 16903 + ... + 18103.

It is an arithmetic number, because the mean of its divisors is an integer number (2747772).

Almost surely, 2^21021103 is an apocalyptic number.

21021103 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21021103 is a deficient number, since it is larger than the sum of its proper divisors (961073).

21021103 is a wasteful number, since it uses less digits than its factorization.

21021103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1985.

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

The square root of 21021103 is about 4584.8776428603. The cubic root of 21021103 is about 275.9848019006.

Adding to 21021103 its reverse (30112012), we get a palindrome (51133115).

Subtracting 21021103 from its reverse (30112012), we obtain a palindrome (9090909).

The spelling of 21021103 in words is "twenty-one million, twenty-one thousand, one hundred three".