21020010210 has 96 divisors (see below), whose sum is σ = 55556532720. Its totient is φ = 5513232384.

The previous prime is 21020010203. The next prime is 21020010223. The reversal of 21020010210 is 1201002012.

It can be written as a sum of positive squares in 8 ways, for example, as 620458281 + 20399551929 = 24909^2 + 142827^2 .

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 = 21020010192 and 21020010201.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 1539132 + ... + 1552728.

Almost surely, 2^21020010210 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21020010210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27778266360).

21020010210 is an abundant number, since it is smaller than the sum of its proper divisors (34536522510).

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

21020010210 is a wasteful number, since it uses less digits than its factorization.

21020010210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13892 (or 13889 counting only the distinct ones).

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

Adding to 21020010210 its reverse (1201002012), we get a palindrome (22221012222).

The spelling of 21020010210 in words is "twenty-one billion, twenty million, ten thousand, two hundred ten".