21321032500 has 60 divisors (see below), whose sum is σ = 46676086996. Its totient is φ = 8519040000.

The previous prime is 21321032479. The next prime is 21321032501. The reversal of 21321032500 is 523012312.

It can be written as a sum of positive squares in 10 ways, for example, as 14038458256 + 7282574244 = 118484^2 + 85338^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321032501) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 2548324 + ... + 2556676.

Almost surely, 2^21321032500 is an apocalyptic number.

21321032500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21321032500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23338043498).

21321032500 is an abundant number, since it is smaller than the sum of its proper divisors (25355054496).

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

21321032500 is a wasteful number, since it uses less digits than its factorization.

21321032500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9398 (or 9381 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 19.

Adding to 21321032500 its reverse (523012312), we get a palindrome (21844044812).

The spelling of 21321032500 in words is "twenty-one billion, three hundred twenty-one million, thirty-two thousand, five hundred".