20816668660 has 24 divisors (see below), whose sum is σ = 46015794720. Its totient is φ = 7888421664.

The previous prime is 20816668651. The next prime is 20816668667. The reversal of 20816668660 is 6686661802.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20816668667) 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, 27389974 + ... + 27390733.

It is an arithmetic number, because the mean of its divisors is an integer number (1917324780).

Almost surely, 2^20816668660 is an apocalyptic number.

20816668660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20816668660 is an abundant number, since it is smaller than the sum of its proper divisors (25199126060).

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

20816668660 is a wasteful number, since it uses less digits than its factorization.

20816668660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54780735 (or 54780733 counting only the distinct ones).

The product of its (nonzero) digits is 995328, while the sum is 49.

The spelling of 20816668660 in words is "twenty billion, eight hundred sixteen million, six hundred sixty-eight thousand, six hundred sixty".