21021220010 has 24 divisors (see below), whose sum is σ = 44015861700. Its totient is φ = 7207275264.

The previous prime is 21021220007. The next prime is 21021220039. The reversal of 21021220010 is 1002212012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 20779510801 + 241709209 = 144151^2 + 15547^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21021219973 and 21021220000.

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 11 ways as a sum of consecutive naturals, for example, 21449735 + ... + 21450714.

Almost surely, 2^21021220010 is an apocalyptic number.

21021220010 is an abundant number, since it is smaller than the sum of its proper divisors (22994641690).

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

21021220010 is a wasteful number, since it uses less digits than its factorization.

21021220010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42900470 (or 42900463 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21021220010 its reverse (1002212012), we get a palindrome (22023432022).

The spelling of 21021220010 in words is "twenty-one billion, twenty-one million, two hundred twenty thousand, ten".