21002020000 has 120 divisors (see below), whose sum is σ = 55643279076. Its totient is φ = 7754496000.

The previous prime is 21002019959. The next prime is 21002020043. The reversal of 21002020000 is 2020012.

It is a happy number.

It can be written as a sum of positive squares in 10 ways, for example, as 327031056 + 20674988944 = 18084^2 + 143788^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 219612 + ... + 300388.

Almost surely, 2^21002020000 is an apocalyptic number.

21002020000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21002020000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27821639538).

21002020000 is an abundant number, since it is smaller than the sum of its proper divisors (34641259076).

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

21002020000 is an equidigital number, since it uses as much as digits as its factorization.

21002020000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80820 (or 80797 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 7.

Adding to 21002020000 its reverse (2020012), we get a palindrome (21004040012).

The spelling of 21002020000 in words is "twenty-one billion, two million, twenty thousand".