21210020010 has 24 divisors (see below), whose sum is σ = 55146052260. Its totient is φ = 5656005312.

The previous prime is 21210020003. The next prime is 21210020053. The reversal of 21210020010 is 1002001212.

It can be written as a sum of positive squares in 2 ways, for example, as 20554096689 + 655923321 = 143367^2 + 25611^2 .

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 = 21210019974 and 21210020001.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 117833355 + ... + 117833534.

Almost surely, 2^21210020010 is an apocalyptic number.

21210020010 is an abundant number, since it is smaller than the sum of its proper divisors (33936032250).

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

21210020010 is a wasteful number, since it uses less digits than its factorization.

21210020010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 235666902 (or 235666899 counting only the distinct ones).

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

Adding to 21210020010 its reverse (1002001212), we get a palindrome (22212021222).

The spelling of 21210020010 in words is "twenty-one billion, two hundred ten million, twenty thousand, ten".