21010100000 has 72 divisors (see below), whose sum is σ = 51701479956. Its totient is φ = 8404000000.

The previous prime is 21010099987. The next prime is 21010100021. The reversal of 21010100000 is 101012.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 6280879504 + 14729220496 = 79252^2 + 121364^2 .

It is a Harshad number since it is a multiple of its sum of digits (5).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5051 + ... + 205050.

Almost surely, 2^21010100000 is an apocalyptic number.

21010100000 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 21010100000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25850739978).

21010100000 is an abundant number, since it is smaller than the sum of its proper divisors (30691379956).

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

21010100000 is an frugal number, since it uses more digits than its factorization.

21010100000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210136 (or 210108 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 5.

Adding to 21010100000 its reverse (101012), we get a palindrome (21010201012).

The spelling of 21010100000 in words is "twenty-one billion, ten million, one hundred thousand".