21021001103 has 4 divisors (see below), whose sum is σ = 21745863240. Its totient is φ = 20296138968.

The previous prime is 21021001097. The next prime is 21021001123. The reversal of 21021001103 is 30110012012.

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-21021001103 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 (21021001123) 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, 362431025 + ... + 362431082.

It is an arithmetic number, because the mean of its divisors is an integer number (5436465810).

Almost surely, 2^21021001103 is an apocalyptic number.

21021001103 is a deficient number, since it is larger than the sum of its proper divisors (724862137).

21021001103 is an equidigital number, since it uses as much as digits as its factorization.

21021001103 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 724862136.

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

Adding to 21021001103 its reverse (30110012012), we get a palindrome (51131013115).

The spelling of 21021001103 in words is "twenty-one billion, twenty-one million, one thousand, one hundred three".