21001707008 has 80 divisors (see below), whose sum is σ = 43853014656. Its totient is φ = 10029127680.

The previous prime is 21001707007. The next prime is 21001707059. The reversal of 21001707008 is 80070710012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001707007) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13788935 + ... + 13790457.

Almost surely, 2^21001707008 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 21001707008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21926507328).

21001707008 is an abundant number, since it is smaller than the sum of its proper divisors (22851307648).

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

21001707008 is a wasteful number, since it uses less digits than its factorization.

21001707008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2735 (or 2719 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 26.

The spelling of 21001707008 in words is "twenty-one billion, one million, seven hundred seven thousand, eight".