21000718128 has 40 divisors (see below), whose sum is σ = 58425076528. Its totient is φ = 6461759232.

The previous prime is 21000718111. The next prime is 21000718139. The reversal of 21000718128 is 82181700012.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21000718095 and 21000718104.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16826875 + ... + 16828122.

Almost surely, 2^21000718128 is an apocalyptic number.

It is an amenable number.

21000718128 is an abundant number, since it is smaller than the sum of its proper divisors (37424358400).

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

21000718128 is a wasteful number, since it uses less digits than its factorization.

21000718128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33655021 (or 33655015 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 30.

The spelling of 21000718128 in words is "twenty-one billion, seven hundred eighteen thousand, one hundred twenty-eight".