21004103124 has 18 divisors (see below), whose sum is σ = 53093705210. Its totient is φ = 7001367696.

The previous prime is 21004103123. The next prime is 21004103129. The reversal of 21004103124 is 42130140012.

It can be written as a sum of positive squares in only one way, i.e., 18586414224 + 2417688900 = 136332^2 + 49170^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21004103097 and 21004103106.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21004103123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 291723619 + ... + 291723690.

Almost surely, 2^21004103124 is an apocalyptic number.

It is an amenable number.

21004103124 is an abundant number, since it is smaller than the sum of its proper divisors (32089602086).

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

21004103124 is a wasteful number, since it uses less digits than its factorization.

21004103124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 583447319 (or 583447314 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21004103124 its reverse (42130140012), we get a palindrome (63134243136).

The spelling of 21004103124 in words is "twenty-one billion, four million, one hundred three thousand, one hundred twenty-four".