21021000210 has 192 divisors, whose sum is σ = 64065500928. Its totient is φ = 4682022912.

The previous prime is 21021000199. The next prime is 21021000223. The reversal of 21021000210 is 1200012012.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21021000192 and 21021000201.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 18230994 + ... + 18232146.

It is an arithmetic number, because the mean of its divisors is an integer number (333674484).

Almost surely, 2^21021000210 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21021000210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32032750464).

21021000210 is an abundant number, since it is smaller than the sum of its proper divisors (43044500718).

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

21021000210 is a wasteful number, since it uses less digits than its factorization.

21021000210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1889 (or 1886 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21021000210 its reverse (1200012012), we get a palindrome (22221012222).

The spelling of 21021000210 in words is "twenty-one billion, twenty-one million, two hundred ten", and thus it is an aban number.