21103011205 has 8 divisors (see below), whose sum is σ = 25574342904. Its totient is φ = 16715256000.

The previous prime is 21103011203. The next prime is 21103011227. The reversal of 21103011205 is 50211030112.

It can be written as a sum of positive squares in 4 ways, for example, as 3617180449 + 17485830756 = 60143^2 + 132234^2 .

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

It is not a de Polignac number, because 21103011205 - 2¹ = 21103011203 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 (21103011203) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20893566 + ... + 20894575.

It is an arithmetic number, because the mean of its divisors is an integer number (3196792863).

Almost surely, 2^21103011205 is an apocalyptic number.

It is an amenable number.

21103011205 is a deficient number, since it is larger than the sum of its proper divisors (4471331699).

21103011205 is a wasteful number, since it uses less digits than its factorization.

21103011205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41788247.

The product of its (nonzero) digits is 60, while the sum is 16.

Adding to 21103011205 its reverse (50211030112), we get a palindrome (71314041317).

The spelling of 21103011205 in words is "twenty-one billion, one hundred three million, eleven thousand, two hundred five".