21121311103 has 4 divisors (see below), whose sum is σ = 21121665568. Its totient is φ = 21120956640.

The previous prime is 21121311077. The next prime is 21121311109. The reversal of 21121311103 is 30111312112.

It is a happy number.

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-21121311103 is a prime.

It is a super-2 number, since 2×21121311103² (a number of 21 digits) 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 (21121311109) 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, 63543 + ... + 215128.

It is an arithmetic number, because the mean of its divisors is an integer number (5280416392).

Almost surely, 2^21121311103 is an apocalyptic number.

21121311103 is a deficient number, since it is larger than the sum of its proper divisors (354465).

21121311103 is an equidigital number, since it uses as much as digits as its factorization.

21121311103 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 354464.

The product of its (nonzero) digits is 36, while the sum is 16.

Adding to 21121311103 its reverse (30111312112), we get a palindrome (51232623215).

The spelling of 21121311103 in words is "twenty-one billion, one hundred twenty-one million, three hundred eleven thousand, one hundred three".