21010000000 has 256 divisors, whose sum is σ = 57374853120. Its totient is φ = 7600000000.

The previous prime is 21009999971. The next prime is 21010000009. The reversal of 21010000000 is 1012.

It is a Harshad number since it is a multiple of its sum of digits (4).

It is not an unprimeable number, because it can be changed into a prime (21010000009) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 109999905 + ... + 110000095.

It is an arithmetic number, because the mean of its divisors is an integer number (224120520).

Almost surely, 2^21010000000 is an apocalyptic number.

21010000000 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 21010000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28687426560).

21010000000 is an abundant number, since it is smaller than the sum of its proper divisors (36364853120).

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

21010000000 is an frugal number, since it uses more digits than its factorization.

21010000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251 (or 209 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 4.

Adding to 21010000000 its reverse (1012), we get a palindrome (21010001012).

The spelling of 21010000000 in words is "twenty-one billion, ten million", and thus it is an aban number and an uban number.