21311013103 has 4 divisors (see below), whose sum is σ = 21311698408. Its totient is φ = 21310327800.

The previous prime is 21311013083. The next prime is 21311013133. The reversal of 21311013103 is 30131011312.

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 21311013103 - 2¹⁷ = 21310882031 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 (21311013133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 293673 + ... + 358978.

It is an arithmetic number, because the mean of its divisors is an integer number (5327924602).

Almost surely, 2^21311013103 is an apocalyptic number.

21311013103 is a deficient number, since it is larger than the sum of its proper divisors (685305).

21311013103 is an equidigital number, since it uses as much as digits as its factorization.

21311013103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 685304.

The product of its (nonzero) digits is 54, while the sum is 16.

Adding to 21311013103 its reverse (30131011312), we get a palindrome (51442024415).

The spelling of 21311013103 in words is "twenty-one billion, three hundred eleven million, thirteen thousand, one hundred three".