20816680 has 32 divisors (see below), whose sum is σ = 47485800. Its totient is φ = 8211456.

The previous prime is 20816669. The next prime is 20816689. The reversal of 20816680 is 8661802.

It can be written as a sum of positive squares in 4 ways, for example, as 18198756 + 2617924 = 4266^2 + 1618^2 .

It is not an unprimeable number, because it can be changed into a prime (20816689) 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, 645 + ... + 6484.

Almost surely, 2^20816680 is an apocalyptic number.

20816680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20816680 is an abundant number, since it is smaller than the sum of its proper divisors (26669120).

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

20816680 is a wasteful number, since it uses less digits than its factorization.

20816680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7213 (or 7209 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 31.

The square root of 20816680 is about 4562.5299999014. The cubic root of 20816680 is about 275.0872670700.

The spelling of 20816680 in words is "twenty million, eight hundred sixteen thousand, six hundred eighty".