21020010020 has 12 divisors (see below), whose sum is σ = 44142021084. Its totient is φ = 8408004000.

The previous prime is 21020010013. The next prime is 21020010041. The reversal of 21020010020 is 2001002012.

It can be written as a sum of positive squares in 2 ways, for example, as 11743623424 + 9276386596 = 108368^2 + 96314^2 .

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 3 ways as a sum of consecutive naturals, for example, 525500231 + ... + 525500270.

It is an arithmetic number, because the mean of its divisors is an integer number (3678501757).

Almost surely, 2^21020010020 is an apocalyptic number.

21020010020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21020010020 is an abundant number, since it is smaller than the sum of its proper divisors (23122011064).

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

21020010020 is a wasteful number, since it uses less digits than its factorization.

21020010020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1051000510 (or 1051000508 counting only the distinct ones).

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

Adding to 21020010020 its reverse (2001002012), we get a palindrome (23021012032).

The spelling of 21020010020 in words is "twenty-one billion, twenty million, ten thousand, twenty".