20643835688 has 32 divisors (see below), whose sum is σ = 44241490560. Its totient is φ = 8846418240.

The previous prime is 20643835631. The next prime is 20643835691. The reversal of 20643835688 is 88653834602.

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, 869333 + ... + 892763.

It is an arithmetic number, because the mean of its divisors is an integer number (1382546580).

Almost surely, 2^20643835688 is an apocalyptic number.

20643835688 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

20643835688 is an abundant number, since it is smaller than the sum of its proper divisors (23597654872).

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

20643835688 is a wasteful number, since it uses less digits than its factorization.

20643835688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39177 (or 39173 counting only the distinct ones).

The product of its (nonzero) digits is 6635520, while the sum is 53.

The spelling of 20643835688 in words is "twenty billion, six hundred forty-three million, eight hundred thirty-five thousand, six hundred eighty-eight".