21000101108 has 72 divisors (see below), whose sum is σ = 43959049344. Its totient is φ = 8747222400.

The previous prime is 21000101107. The next prime is 21000101141. The reversal of 21000101108 is 80110100012.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a junction number, because it is equal to n+sod(n) for n = 21000101092 and 21000101101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000101107) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2172935 + ... + 2182577.

It is an arithmetic number, because the mean of its divisors is an integer number (610542352).

Almost surely, 2^21000101108 is an apocalyptic number.

21000101108 is a gapful number since it is divisible by the number (28) 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 21000101108, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21979524672).

21000101108 is an abundant number, since it is smaller than the sum of its proper divisors (22958948236).

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

21000101108 is a wasteful number, since it uses less digits than its factorization.

21000101108 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9973 (or 9964 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 14.

The spelling of 21000101108 in words is "twenty-one billion, one hundred one thousand, one hundred eight".