21005210000 has 200 divisors, whose sum is σ = 53420699904. Its totient is φ = 7983360000.

The previous prime is 21005209993. The next prime is 21005210003. The reversal of 21005210000 is 1250012.

It is a tau number, because it is divible by the number of its divisors (200).

It is not an unprimeable number, because it can be changed into a prime (21005210003) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 62329832 + ... + 62330168.

Almost surely, 2^21005210000 is an apocalyptic number.

21005210000 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 21005210000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26710349952).

21005210000 is an abundant number, since it is smaller than the sum of its proper divisors (32415489904).

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

21005210000 is a wasteful number, since it uses less digits than its factorization.

21005210000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 659 (or 638 counting only the distinct ones).

The product of its (nonzero) digits is 20, while the sum is 11.

Adding to 21005210000 its reverse (1250012), we get a palindrome (21006460012).

The spelling of 21005210000 in words is "twenty-one billion, five million, two hundred ten thousand".