21312021103 has 4 divisors (see below), whose sum is σ = 21318923520. Its totient is φ = 21305118688.

The previous prime is 21312021077. The next prime is 21312021109. The reversal of 21312021103 is 30112021312.

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 21312021103 - 2²¹ = 21309923951 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 (21312021109) 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, 3446575 + ... + 3452752.

It is an arithmetic number, because the mean of its divisors is an integer number (5329730880).

Almost surely, 2^21312021103 is an apocalyptic number.

21312021103 is a deficient number, since it is larger than the sum of its proper divisors (6902417).

21312021103 is an equidigital number, since it uses as much as digits as its factorization.

21312021103 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6902416.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21312021103 its reverse (30112021312), we get a palindrome (51424042415).

The spelling of 21312021103 in words is "twenty-one billion, three hundred twelve million, twenty-one thousand, one hundred three".