21001110208 has 224 divisors, whose sum is σ = 49502251008. Its totient is φ = 8747827200.

The previous prime is 21001110199. The next prime is 21001110209. The reversal of 21001110208 is 80201110012.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a junction number, because it is equal to n+sod(n) for n = 21001110191 and 21001110200.

It is not an unprimeable number, because it can be changed into a prime (21001110209) 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, 92515791 + ... + 92516017.

It is an arithmetic number, because the mean of its divisors is an integer number (220992192).

Almost surely, 2^21001110208 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21001110208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24751125504).

21001110208 is an abundant number, since it is smaller than the sum of its proper divisors (28501140800).

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

21001110208 is a wasteful number, since it uses less digits than its factorization.

21001110208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 511 (or 501 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 16.

The spelling of 21001110208 in words is "twenty-one billion, one million, one hundred ten thousand, two hundred eight".