21002001103 has 4 divisors (see below), whose sum is σ = 21044775528. Its totient is φ = 20959226680.

The previous prime is 21002001091. The next prime is 21002001107. The reversal of 21002001103 is 30110020012.

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-21002001103 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 21002001103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002001107) 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, 21386476 + ... + 21387457.

It is an arithmetic number, because the mean of its divisors is an integer number (5261193882).

Almost surely, 2^21002001103 is an apocalyptic number.

21002001103 is a deficient number, since it is larger than the sum of its proper divisors (42774425).

21002001103 is an equidigital number, since it uses as much as digits as its factorization.

21002001103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42774424.

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

Adding to 21002001103 its reverse (30110020012), we get a palindrome (51112021115).

The spelling of 21002001103 in words is "twenty-one billion, two million, one thousand, one hundred three".