21121103 has 4 divisors (see below), whose sum is σ = 22232760. Its totient is φ = 20009448.

The previous prime is 21121099. The next prime is 21121129. The reversal of 21121103 is 30112112.

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 21121103 - 2² = 21121099 is a prime.

It is a super-2 number, since 2×21121103² = 892201983873218, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121003) 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, 555800 + ... + 555837.

It is an arithmetic number, because the mean of its divisors is an integer number (5558190).

Almost surely, 2^21121103 is an apocalyptic number.

21121103 is a deficient number, since it is larger than the sum of its proper divisors (1111657).

21121103 is a wasteful number, since it uses less digits than its factorization.

21121103 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1111656.

The product of its (nonzero) digits is 12, while the sum is 11.

The square root of 21121103 is about 4595.7701204477. The cubic root of 21121103 is about 276.4217411096.

Adding to 21121103 its reverse (30112112), we get a palindrome (51233215).

The spelling of 21121103 in words is "twenty-one million, one hundred twenty-one thousand, one hundred three".