21531003104 has 192 divisors, whose sum is σ = 48073798080. Its totient is φ = 9429073920.

The previous prime is 21531003077. The next prime is 21531003127. The reversal of 21531003104 is 40130013512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 109294334 + ... + 109294530.

It is an arithmetic number, because the mean of its divisors is an integer number (250384365).

Almost surely, 2^21531003104 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 21531003104, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24036899040).

21531003104 is an abundant number, since it is smaller than the sum of its proper divisors (26542794976).

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

21531003104 is a wasteful number, since it uses less digits than its factorization.

21531003104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 413 (or 405 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 20.

Adding to 21531003104 its reverse (40130013512), we get a palindrome (61661016616).

The spelling of 21531003104 in words is "twenty-one billion, five hundred thirty-one million, three thousand, one hundred four".