21123131103 has 16 divisors (see below), whose sum is σ = 31433866240. Its totient is φ = 14018935032.

The previous prime is 21123131083. The next prime is 21123131147. The reversal of 21123131103 is 30113132112.

It is not a de Polignac number, because 21123131103 - 2¹⁰ = 21123130079 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 (21123131173) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1748101 + ... + 1760142.

It is an arithmetic number, because the mean of its divisors is an integer number (1964616640).

Almost surely, 2^21123131103 is an apocalyptic number.

21123131103 is a deficient number, since it is larger than the sum of its proper divisors (10310735137).

21123131103 is a wasteful number, since it uses less digits than its factorization.

21123131103 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3508475 (or 3508469 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

Adding to 21123131103 its reverse (30113132112), we get a palindrome (51236263215).

The spelling of 21123131103 in words is "twenty-one billion, one hundred twenty-three million, one hundred thirty-one thousand, one hundred three".