21100020008 has 16 divisors (see below), whose sum is σ = 39633573780. Its totient is φ = 10531067008.

The previous prime is 21100020001. The next prime is 21100020023. The reversal of 21100020008 is 80002000112.

It can be written as a sum of positive squares in 2 ways, for example, as 21012821764 + 87198244 = 144958^2 + 9338^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21100019974 and 21100020001.

It is not an unprimeable number, because it can be changed into a prime (21100020001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2363141 + ... + 2372052.

Almost surely, 2^21100020008 is an apocalyptic number.

It is an amenable number.

21100020008 is a deficient number, since it is larger than the sum of its proper divisors (18533553772).

21100020008 is a wasteful number, since it uses less digits than its factorization.

21100020008 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4735756 (or 4735752 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

The spelling of 21100020008 in words is "twenty-one billion, one hundred million, twenty thousand, eight".