21031103104 has 128 divisors (see below), whose sum is σ = 49705513920. Its totient is φ = 8753725440.

The previous prime is 21031103069. The next prime is 21031103117. The reversal of 21031103104 is 40130113012.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (16).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 873759 + ... + 897505.

Almost surely, 2^21031103104 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21031103104, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24852756960).

21031103104 is an abundant number, since it is smaller than the sum of its proper divisors (28674410816).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21031103104 is a wasteful number, since it uses less digits than its factorization.

21031103104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23826 (or 23814 counting only the distinct ones).

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

Adding to 21031103104 its reverse (40130113012), we get a palindrome (61161216116).

The spelling of 21031103104 in words is "twenty-one billion, thirty-one million, one hundred three thousand, one hundred four".